Hugging Face's logo

Buckets:
ranranrunforit
/
build-small-hackathon-storage

Files
xet
ranranrunforit/build-small-hackathon-storage / pylibs /numpy /ma /core.py
ranranrunforit's picture
ranranrunforit
download
raw
289 kB
"""
numpy.ma : a package to handle missing or invalid values.
This package was initially written for numarray by Paul F. Dubois
at Lawrence Livermore National Laboratory.
In 2006, the package was completely rewritten by Pierre Gerard-Marchant
(University of Georgia) to make the MaskedArray class a subclass of ndarray,
and to improve support of structured arrays.
Copyright 1999, 2000, 2001 Regents of the University of California.
Released for unlimited redistribution.
* Adapted for numpy_core 2005 by Travis Oliphant and (mainly) Paul Dubois.
* Subclassing of the base `ndarray` 2006 by Pierre Gerard-Marchant
 (pgmdevlist_AT_gmail_DOT_com)
* Improvements suggested by Reggie Dugard (reggie_AT_merfinllc_DOT_com)
.. moduleauthor:: Pierre Gerard-Marchant
"""
import builtins
import functools
import inspect
import operator
import re
import textwrap
import warnings
import numpy as np
import numpy._core.numerictypes as ntypes
import numpy._core.umath as umath
from numpy import (
 _NoValue,
 amax,
 amin,
 angle,
 array as narray, # noqa: F401
 bool_,
 expand_dims,
 finfo, # noqa: F401
 iinfo, # noqa: F401
 iscomplexobj,
 ndarray,
)
from numpy._core import multiarray as mu
from numpy._core.numeric import normalize_axis_tuple
from numpy._utils import set_module
__all__ = [
 'MAError', 'MaskError', 'MaskType', 'MaskedArray', 'abs', 'absolute',
 'add', 'all', 'allclose', 'allequal', 'alltrue', 'amax', 'amin',
 'angle', 'anom', 'anomalies', 'any', 'append', 'arange', 'arccos',
 'arccosh', 'arcsin', 'arcsinh', 'arctan', 'arctan2', 'arctanh',
 'argmax', 'argmin', 'argsort', 'around', 'array', 'asanyarray',
 'asarray', 'bitwise_and', 'bitwise_or', 'bitwise_xor', 'bool_', 'ceil',
 'choose', 'clip', 'common_fill_value', 'compress', 'compressed',
 'concatenate', 'conjugate', 'convolve', 'copy', 'correlate', 'cos', 'cosh',
 'count', 'cumprod', 'cumsum', 'default_fill_value', 'diag', 'diagonal',
 'diff', 'divide', 'empty', 'empty_like', 'equal', 'exp',
 'expand_dims', 'fabs', 'filled', 'fix_invalid', 'flatten_mask',
 'flatten_structured_array', 'floor', 'floor_divide', 'fmod',
 'frombuffer', 'fromflex', 'fromfunction', 'getdata', 'getmask',
 'getmaskarray', 'greater', 'greater_equal', 'harden_mask', 'hypot',
 'identity', 'ids', 'indices', 'inner', 'innerproduct', 'isMA',
 'isMaskedArray', 'is_mask', 'is_masked', 'isarray', 'left_shift',
 'less', 'less_equal', 'log', 'log10', 'log2',
 'logical_and', 'logical_not', 'logical_or', 'logical_xor', 'make_mask',
 'make_mask_descr', 'make_mask_none', 'mask_or', 'masked',
 'masked_array', 'masked_equal', 'masked_greater',
 'masked_greater_equal', 'masked_inside', 'masked_invalid',
 'masked_less', 'masked_less_equal', 'masked_not_equal',
 'masked_object', 'masked_outside', 'masked_print_option',
 'masked_singleton', 'masked_values', 'masked_where', 'max', 'maximum',
 'maximum_fill_value', 'mean', 'min', 'minimum', 'minimum_fill_value',
 'mod', 'multiply', 'mvoid', 'ndim', 'negative', 'nomask', 'nonzero',
 'not_equal', 'ones', 'ones_like', 'outer', 'outerproduct', 'power', 'prod',
 'product', 'ptp', 'put', 'putmask', 'ravel', 'remainder',
 'repeat', 'reshape', 'resize', 'right_shift', 'round', 'round_',
 'set_fill_value', 'shape', 'sin', 'sinh', 'size', 'soften_mask',
 'sometrue', 'sort', 'sqrt', 'squeeze', 'std', 'subtract', 'sum',
 'swapaxes', 'take', 'tan', 'tanh', 'trace', 'transpose', 'true_divide',
 'var', 'where', 'zeros', 'zeros_like',
 ]
MaskType = np.bool
nomask = MaskType(0)
class MaskedArrayFutureWarning(FutureWarning):
 pass
def _deprecate_argsort_axis(arr):
 """
 Adjust the axis passed to argsort, warning if necessary
 Parameters
 ----------
 arr
 The array which argsort was called on
 np.ma.argsort has a long-term bug where the default of the axis argument
 is wrong (gh-8701), which now must be kept for backwards compatibility.
 Thankfully, this only makes a difference when arrays are 2- or more-
 dimensional, so we only need a warning then.
 """
 if arr.ndim <= 1:
 # no warning needed - but switch to -1 anyway, to avoid surprising
 # subclasses, which are more likely to implement scalar axes.
 return -1
 else:
 # 2017-04-11, Numpy 1.13.0, gh-8701: warn on axis default
 warnings.warn(
 "In the future the default for argsort will be axis=-1, not the "
 "current None, to match its documentation and np.argsort. "
 "Explicitly pass -1 or None to silence this warning.",
 MaskedArrayFutureWarning, stacklevel=3)
 return None
def doc_note(initialdoc, note):
 """
 Adds a Notes section to an existing docstring.
 """
 if initialdoc is None:
 return
 if note is None:
 return initialdoc
notesplit = re.split(r'\n\s*?Notes\n\s*?-----', inspect.cleandoc(initialdoc))
 notedoc = f"\n\nNotes\n-----\n{inspect.cleandoc(note)}\n"
return ''.join(notesplit[:1] + [notedoc] + notesplit[1:])
###############################################################################
# Exceptions #
###############################################################################
class MAError(Exception):
 """
 Class for masked array related errors.
 """
 pass
class MaskError(MAError):
 """
 Class for mask related errors.
 """
 pass
###############################################################################
# Filling options #
###############################################################################
# b: boolean - c: complex - f: floats - i: integer - O: object - S: string
default_filler = {'b': True,
 'c': 1.e20 + 0.0j,
 'f': 1.e20,
 'i': 999999,
 'O': '?',
 'S': b'N/A',
 'u': 999999,
 'V': b'???',
 'U': 'N/A',
 'T': 'N/A'
 }
# Add datetime64 and timedelta64 types
for v in ["Y", "M", "W", "D", "h", "m", "s", "ms", "us", "ns", "ps",
 "fs", "as"]:
 default_filler["M8[" + v + "]"] = np.datetime64("NaT", v)
 default_filler["m8[" + v + "]"] = np.timedelta64("NaT", v)
float_types_list = [np.half, np.single, np.double, np.longdouble,
 np.csingle, np.cdouble, np.clongdouble]
_minvals: dict[type, int] = {}
_maxvals: dict[type, int] = {}
for sctype in ntypes.sctypeDict.values():
 scalar_dtype = np.dtype(sctype)
if scalar_dtype.kind in "Mm":
 info = np.iinfo(np.int64)
 min_val, max_val = info.min + 1, info.max
 elif np.issubdtype(scalar_dtype, np.integer):
 info = np.iinfo(sctype)
 min_val, max_val = info.min, info.max
 elif np.issubdtype(scalar_dtype, np.floating):
 info = np.finfo(sctype)
 min_val, max_val = info.min, info.max
 elif scalar_dtype.kind == "b":
 min_val, max_val = 0, 1
 else:
 min_val, max_val = None, None
_minvals[sctype] = min_val
 _maxvals[sctype] = max_val
max_filler = _minvals
max_filler.update([(k, -np.inf) for k in float_types_list[:4]])
max_filler.update([(k, complex(-np.inf, -np.inf)) for k in float_types_list[-3:]])
min_filler = _maxvals
min_filler.update([(k, +np.inf) for k in float_types_list[:4]])
min_filler.update([(k, complex(+np.inf, +np.inf)) for k in float_types_list[-3:]])
del float_types_list
def _recursive_fill_value(dtype, f):
 """
 Recursively produce a fill value for `dtype`, calling f on scalar dtypes
 """
 if dtype.names is not None:
 # We wrap into `array` here, which ensures we use NumPy cast rules
 # for integer casts, this allows the use of 99999 as a fill value
 # for int8.
 # TODO: This is probably a mess, but should best preserve behavior?
 vals = tuple(
 np.array(_recursive_fill_value(dtype[name], f))
 for name in dtype.names)
 return np.array(vals, dtype=dtype)[()] # decay to void scalar from 0d
 elif dtype.subdtype:
 subtype, shape = dtype.subdtype
 subval = _recursive_fill_value(subtype, f)
 return np.full(shape, subval)
 else:
 return f(dtype)
def _get_dtype_of(obj):
 """ Convert the argument for *_fill_value into a dtype """
 if isinstance(obj, np.dtype):
 return obj
 elif hasattr(obj, 'dtype'):
 return obj.dtype
 else:
 return np.asanyarray(obj).dtype
def default_fill_value(obj):
 """
 Return the default fill value for the argument object.
 The default filling value depends on the datatype of the input
 array or the type of the input scalar:
 =========== ========
 datatype default
 =========== ========
 bool True
 int 999999
 float 1.e20
 complex 1.e20+0j
 object '?'
 string 'N/A'
 StringDType 'N/A'
 =========== ========
 For structured types, a structured scalar is returned, with each field the
 default fill value for its type.
 For subarray types, the fill value is an array of the same size containing
 the default scalar fill value.
 Parameters
 ----------
 obj : ndarray, dtype or scalar
 The array data-type or scalar for which the default fill value
 is returned.
 Returns
 -------
 fill_value : scalar
 The default fill value.
 Examples
 --------
 >>> import numpy as np
 >>> np.ma.default_fill_value(1)
 999999
 >>> np.ma.default_fill_value(np.array([1.1, 2., np.pi]))
 1e+20
 >>> np.ma.default_fill_value(np.dtype(complex))
 (1e+20+0j)
 """
 def _scalar_fill_value(dtype):
 if dtype.kind in 'Mm':
 return default_filler.get(dtype.str[1:], '?')
 else:
 return default_filler.get(dtype.kind, '?')
dtype = _get_dtype_of(obj)
 return _recursive_fill_value(dtype, _scalar_fill_value)
def _extremum_fill_value(obj, extremum, extremum_name):
def _scalar_fill_value(dtype):
 try:
 return extremum[dtype.type]
 except KeyError as e:
 raise TypeError(
 f"Unsuitable type {dtype} for calculating {extremum_name}."
 ) from None
dtype = _get_dtype_of(obj)
 return _recursive_fill_value(dtype, _scalar_fill_value)
def minimum_fill_value(obj):
 """
 Return the maximum value that can be represented by the dtype of an object.
 This function is useful for calculating a fill value suitable for
 taking the minimum of an array with a given dtype.
 Parameters
 ----------
 obj : ndarray, dtype or scalar
 An object that can be queried for it's numeric type.
 Returns
 -------
 val : scalar
 The maximum representable value.
 Raises
 ------
 TypeError
 If `obj` isn't a suitable numeric type.
 See Also
 --------
 maximum_fill_value : The inverse function.
 set_fill_value : Set the filling value of a masked array.
 MaskedArray.fill_value : Return current fill value.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = np.int8()
 >>> ma.minimum_fill_value(a)
 127
 >>> a = np.int32()
 >>> ma.minimum_fill_value(a)
 2147483647
 An array of numeric data can also be passed.
 >>> a = np.array([1, 2, 3], dtype=np.int8)
 >>> ma.minimum_fill_value(a)
 127
 >>> a = np.array([1, 2, 3], dtype=np.float32)
 >>> ma.minimum_fill_value(a)
 inf
 """
 return _extremum_fill_value(obj, min_filler, "minimum")
def maximum_fill_value(obj):
 """
 Return the minimum value that can be represented by the dtype of an object.
 This function is useful for calculating a fill value suitable for
 taking the maximum of an array with a given dtype.
 Parameters
 ----------
 obj : ndarray, dtype or scalar
 An object that can be queried for it's numeric type.
 Returns
 -------
 val : scalar
 The minimum representable value.
 Raises
 ------
 TypeError
 If `obj` isn't a suitable numeric type.
 See Also
 --------
 minimum_fill_value : The inverse function.
 set_fill_value : Set the filling value of a masked array.
 MaskedArray.fill_value : Return current fill value.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = np.int8()
 >>> ma.maximum_fill_value(a)
 -128
 >>> a = np.int32()
 >>> ma.maximum_fill_value(a)
 -2147483648
 An array of numeric data can also be passed.
 >>> a = np.array([1, 2, 3], dtype=np.int8)
 >>> ma.maximum_fill_value(a)
 -128
 >>> a = np.array([1, 2, 3], dtype=np.float32)
 >>> ma.maximum_fill_value(a)
 -inf
 """
 return _extremum_fill_value(obj, max_filler, "maximum")
def _recursive_set_fill_value(fillvalue, dt):
 """
 Create a fill value for a structured dtype.
 Parameters
 ----------
 fillvalue : scalar or array_like
 Scalar or array representing the fill value. If it is of shorter
 length than the number of fields in dt, it will be resized.
 dt : dtype
 The structured dtype for which to create the fill value.
 Returns
 -------
 val : tuple
 A tuple of values corresponding to the structured fill value.
 """
 fillvalue = np.resize(fillvalue, len(dt.names))
 output_value = []
 for (fval, name) in zip(fillvalue, dt.names):
 cdtype = dt[name]
 if cdtype.subdtype:
 cdtype = cdtype.subdtype[0]
if cdtype.names is not None:
 output_value.append(tuple(_recursive_set_fill_value(fval, cdtype)))
 else:
 output_value.append(np.array(fval, dtype=cdtype).item())
 return tuple(output_value)
def _check_fill_value(fill_value, ndtype):
 """
 Private function validating the given `fill_value` for the given dtype.
 If fill_value is None, it is set to the default corresponding to the dtype.
 If fill_value is not None, its value is forced to the given dtype.
 The result is always a 0d array.
 """
 ndtype = np.dtype(ndtype)
 if fill_value is None:
 fill_value = default_fill_value(ndtype)
 # TODO: It seems better to always store a valid fill_value, the oddity
 # about is that `_fill_value = None` would behave even more
 # different then.
 # (e.g. this allows arr_uint8.astype(int64) to have the default
 # fill value again...)
 # The one thing that changed in 2.0/2.1 around cast safety is that the
 # default `int(99...)` is not a same-kind cast anymore, so if we
 # have a uint, use the default uint.
 if ndtype.kind == "u":
 fill_value = np.uint(fill_value)
 elif ndtype.names is not None:
 if isinstance(fill_value, (ndarray, np.void)):
 try:
 fill_value = np.asarray(fill_value, dtype=ndtype)
 except ValueError as e:
 err_msg = "Unable to transform %s to dtype %s"
 raise ValueError(err_msg % (fill_value, ndtype)) from e
 else:
 fill_value = np.asarray(fill_value, dtype=object)
 fill_value = np.array(_recursive_set_fill_value(fill_value, ndtype),
 dtype=ndtype)
 elif isinstance(fill_value, str) and (ndtype.char not in 'OSTVU'):
 # Note this check doesn't work if fill_value is not a scalar
 err_msg = "Cannot set fill value of string with array of dtype %s"
 raise TypeError(err_msg % ndtype)
 else:
 # In case we want to convert 1e20 to int.
 # Also in case of converting string arrays.
 try:
 fill_value = np.asarray(fill_value, dtype=ndtype)
 except (OverflowError, ValueError) as e:
 # Raise TypeError instead of OverflowError or ValueError.
 # OverflowError is seldom used, and the real problem here is
 # that the passed fill_value is not compatible with the ndtype.
 err_msg = "Cannot convert fill_value %s to dtype %s"
 raise TypeError(err_msg % (fill_value, ndtype)) from e
 return np.array(fill_value)
def set_fill_value(a, fill_value):
 """
 Set the filling value of a, if a is a masked array.
 This function changes the fill value of the masked array `a` in place.
 If `a` is not a masked array, the function returns silently, without
 doing anything.
 Parameters
 ----------
 a : array_like
 Input array.
 fill_value : dtype
 Filling value. A consistency test is performed to make sure
 the value is compatible with the dtype of `a`.
 Returns
 -------
 None
 Nothing returned by this function.
 See Also
 --------
 maximum_fill_value : Return the default fill value for a dtype.
 MaskedArray.fill_value : Return current fill value.
 MaskedArray.set_fill_value : Equivalent method.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = np.arange(5)
 >>> a
 array([0, 1, 2, 3, 4])
 >>> a = ma.masked_where(a < 3, a)
 >>> a
 masked_array(data=[--, --, --, 3, 4],
 mask=[ True, True, True, False, False],
 fill_value=999999)
 >>> ma.set_fill_value(a, -999)
 >>> a
 masked_array(data=[--, --, --, 3, 4],
 mask=[ True, True, True, False, False],
 fill_value=-999)
 Nothing happens if `a` is not a masked array.
 >>> a = list(range(5))
 >>> a
 [0, 1, 2, 3, 4]
 >>> ma.set_fill_value(a, 100)
 >>> a
 [0, 1, 2, 3, 4]
 >>> a = np.arange(5)
 >>> a
 array([0, 1, 2, 3, 4])
 >>> ma.set_fill_value(a, 100)
 >>> a
 array([0, 1, 2, 3, 4])
 """
 if isinstance(a, MaskedArray):
 a.set_fill_value(fill_value)
def get_fill_value(a):
 """
 Return the filling value of a, if any. Otherwise, returns the
 default filling value for that type.
 """
 if isinstance(a, MaskedArray):
 result = a.fill_value
 else:
 result = default_fill_value(a)
 return result
def common_fill_value(a, b):
 """
 Return the common filling value of two masked arrays, if any.
 If ``a.fill_value == b.fill_value``, return the fill value,
 otherwise return None.
 Parameters
 ----------
 a, b : MaskedArray
 The masked arrays for which to compare fill values.
 Returns
 -------
 fill_value : scalar or None
 The common fill value, or None.
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array([0, 1.], fill_value=3)
 >>> y = np.ma.array([0, 1.], fill_value=3)
 >>> np.ma.common_fill_value(x, y)
 3.0
 """
 t1 = get_fill_value(a)
 t2 = get_fill_value(b)
 if t1 == t2:
 return t1
 return None
def filled(a, fill_value=None):
 """
 Return input as an `~numpy.ndarray`, with masked values replaced by
 `fill_value`.
 If `a` is not a `MaskedArray`, `a` itself is returned.
 If `a` is a `MaskedArray` with no masked values, then ``a.data`` is
 returned.
 If `a` is a `MaskedArray` and `fill_value` is None, `fill_value` is set to
 ``a.fill_value``.
 Parameters
 ----------
 a : MaskedArray or array_like
 An input object.
 fill_value : array_like, optional.
 Can be scalar or non-scalar. If non-scalar, the
 resulting filled array should be broadcastable
 over input array. Default is None.
 Returns
 -------
 a : ndarray
 The filled array.
 See Also
 --------
 compressed
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> x = ma.array(np.arange(9).reshape(3, 3), mask=[[1, 0, 0],
 ... [1, 0, 0],
 ... [0, 0, 0]])
 >>> x.filled()
 array([[999999, 1, 2],
 [999999, 4, 5],
 [ 6, 7, 8]])
 >>> x.filled(fill_value=333)
 array([[333, 1, 2],
 [333, 4, 5],
 [ 6, 7, 8]])
 >>> x.filled(fill_value=np.arange(3))
 array([[0, 1, 2],
 [0, 4, 5],
 [6, 7, 8]])
 """
 if hasattr(a, 'filled'):
 return a.filled(fill_value)
elif isinstance(a, ndarray):
 # Should we check for contiguity ? and a.flags['CONTIGUOUS']:
 return a
 elif isinstance(a, dict):
 return np.array(a, 'O')
 else:
 return np.array(a)
def get_masked_subclass(*arrays):
 """
 Return the youngest subclass of MaskedArray from a list of (masked) arrays.
 In case of siblings, the first listed takes over.
 """
 if len(arrays) == 1:
 arr = arrays[0]
 if isinstance(arr, MaskedArray):
 rcls = type(arr)
 else:
 rcls = MaskedArray
 else:
 arrcls = [type(a) for a in arrays]
 rcls = arrcls[0]
 if not issubclass(rcls, MaskedArray):
 rcls = MaskedArray
 for cls in arrcls[1:]:
 if issubclass(cls, rcls):
 rcls = cls
 # Don't return MaskedConstant as result: revert to MaskedArray
 if rcls.__name__ == 'MaskedConstant':
 return MaskedArray
 return rcls
def getdata(a, subok=True):
 """
 Return the data of a masked array as an ndarray.
 Return the data of `a` (if any) as an ndarray if `a` is a ``MaskedArray``,
 else return `a` as a ndarray or subclass (depending on `subok`) if not.
 Parameters
 ----------
 a : array_like
 Input ``MaskedArray``, alternatively a ndarray or a subclass thereof.
 subok : bool
 Whether to force the output to be a `pure` ndarray (False) or to
 return a subclass of ndarray if appropriate (True, default).
 See Also
 --------
 getmask : Return the mask of a masked array, or nomask.
 getmaskarray : Return the mask of a masked array, or full array of False.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = ma.masked_equal([[1,2],[3,4]], 2)
 >>> a
 masked_array(
 data=[[1, --],
 [3, 4]],
 mask=[[False, True],
 [False, False]],
 fill_value=2)
 >>> ma.getdata(a)
 array([[1, 2],
 [3, 4]])
 Equivalently use the ``MaskedArray`` `data` attribute.
 >>> a.data
 array([[1, 2],
 [3, 4]])
 """
 try:
 data = a._data
 except AttributeError:
 data = np.array(a, copy=None, subok=subok)
 if not subok:
 return data.view(ndarray)
 return data
get_data = getdata
def fix_invalid(a, mask=nomask, copy=True, fill_value=None):
 """
 Return input with invalid data masked and replaced by a fill value.
 Invalid data means values of `nan`, `inf`, etc.
 Parameters
 ----------
 a : array_like
 Input array, a (subclass of) ndarray.
 mask : sequence, optional
 Mask. Must be convertible to an array of booleans with the same
 shape as `data`. True indicates a masked (i.e. invalid) data.
 copy : bool, optional
 Whether to use a copy of `a` (True) or to fix `a` in place (False).
 Default is True.
 fill_value : scalar, optional
 Value used for fixing invalid data. Default is None, in which case
 the ``a.fill_value`` is used.
 Returns
 -------
 b : MaskedArray
 The input array with invalid entries fixed.
 Notes
 -----
 A copy is performed by default.
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array([1., -1, np.nan, np.inf], mask=[1] + [0]*3)
 >>> x
 masked_array(data=[--, -1.0, nan, inf],
 mask=[ True, False, False, False],
 fill_value=1e+20)
 >>> np.ma.fix_invalid(x)
 masked_array(data=[--, -1.0, --, --],
 mask=[ True, False, True, True],
 fill_value=1e+20)
 >>> fixed = np.ma.fix_invalid(x)
 >>> fixed.data
 array([ 1.e+00, -1.e+00, 1.e+20, 1.e+20])
 >>> x.data
 array([ 1., -1., nan, inf])
 """
 a = masked_array(a, copy=copy, mask=mask, subok=True)
 invalid = np.logical_not(np.isfinite(a._data))
 if not invalid.any():
 return a
 a._mask |= invalid
 if fill_value is None:
 fill_value = a.fill_value
 a._data[invalid] = fill_value
 return a
def is_string_or_list_of_strings(val):
 return (isinstance(val, str) or
 (isinstance(val, list) and val and
 builtins.all(isinstance(s, str) for s in val)))
###############################################################################
# Ufuncs #
###############################################################################
ufunc_domain = {}
ufunc_fills = {}
class _DomainCheckInterval:
 """
 Define a valid interval, so that :
 ``domain_check_interval(a,b)(x) == True`` where
 ``x < a`` or ``x > b``.
 """
def __init__(self, a, b):
 "domain_check_interval(a,b)(x) = true where x < a or y > b"
 if a > b:
 (a, b) = (b, a)
 self.a = a
 self.b = b
def __call__(self, x):
 "Execute the call behavior."
 # nans at masked positions cause RuntimeWarnings, even though
 # they are masked. To avoid this we suppress warnings.
 with np.errstate(invalid='ignore'):
 return umath.logical_or(umath.greater(x, self.b),
 umath.less(x, self.a))
class _DomainTan:
 """
 Define a valid interval for the `tan` function, so that:
 ``domain_tan(eps) = True`` where ``abs(cos(x)) < eps``
 """
def __init__(self, eps):
 "domain_tan(eps) = true where abs(cos(x)) < eps)"
 self.eps = eps
def __call__(self, x):
 "Executes the call behavior."
 with np.errstate(invalid='ignore'):
 return umath.less(umath.absolute(umath.cos(x)), self.eps)
class _DomainSafeDivide:
 """
 Define a domain for safe division.
 """
def __init__(self, tolerance=None):
 self.tolerance = tolerance
def __call__(self, a, b):
 # Delay the selection of the tolerance to here in order to reduce numpy
 # import times. The calculation of these parameters is a substantial
 # component of numpy's import time.
 if self.tolerance is None:
 self.tolerance = np.finfo(float).tiny
 # don't call ma ufuncs from __array_wrap__ which would fail for scalars
 a, b = np.asarray(a), np.asarray(b)
 with np.errstate(all='ignore'):
 return umath.absolute(a) * self.tolerance >= umath.absolute(b)
class _DomainGreater:
 """
 DomainGreater(v)(x) is True where x <= v.
 """
def __init__(self, critical_value):
 "DomainGreater(v)(x) = true where x <= v"
 self.critical_value = critical_value
def __call__(self, x):
 "Executes the call behavior."
 with np.errstate(invalid='ignore'):
 return umath.less_equal(x, self.critical_value)
class _DomainGreaterEqual:
 """
 DomainGreaterEqual(v)(x) is True where x < v.
 """
def __init__(self, critical_value):
 "DomainGreaterEqual(v)(x) = true where x < v"
 self.critical_value = critical_value
def __call__(self, x):
 "Executes the call behavior."
 with np.errstate(invalid='ignore'):
 return umath.less(x, self.critical_value)
class _MaskedUFunc:
 def __init__(self, ufunc):
 self.f = ufunc
 self.__doc__ = ufunc.__doc__
 self.__name__ = ufunc.__name__
 self.__qualname__ = ufunc.__qualname__
def __str__(self):
 return f"Masked version of {self.f}"
class _MaskedUnaryOperation(_MaskedUFunc):
 """
 Defines masked version of unary operations, where invalid values are
 pre-masked.
 Parameters
 ----------
 mufunc : callable
 The function for which to define a masked version. Made available
 as ``_MaskedUnaryOperation.f``.
 fill : scalar, optional
 Filling value, default is 0.
 domain : class instance
 Domain for the function. Should be one of the ``_Domain*``
 classes. Default is None.
 """
def __init__(self, mufunc, fill=0, domain=None):
 super().__init__(mufunc)
 self.fill = fill
 self.domain = domain
 ufunc_domain[mufunc] = domain
 ufunc_fills[mufunc] = fill
def __call__(self, a, *args, **kwargs):
 """
 Execute the call behavior.
 """
 d = getdata(a)
 # Deal with domain
 if self.domain is not None:
 # Case 1.1. : Domained function
 # nans at masked positions cause RuntimeWarnings, even though
 # they are masked. To avoid this we suppress warnings.
 with np.errstate(divide='ignore', invalid='ignore'):
 result = self.f(d, *args, **kwargs)
 # Make a mask
 m = ~umath.isfinite(result)
 m |= self.domain(d)
 m |= getmask(a)
 else:
 # Case 1.2. : Function without a domain
 # Get the result and the mask
 with np.errstate(divide='ignore', invalid='ignore'):
 result = self.f(d, *args, **kwargs)
 m = getmask(a)
if not result.ndim:
 # Case 2.1. : The result is scalarscalar
 if m:
 return masked
 return result
if m is not nomask:
 # Case 2.2. The result is an array
 # We need to fill the invalid data back w/ the input Now,
 # that's plain silly: in C, we would just skip the element and
 # keep the original, but we do have to do it that way in Python
# In case result has a lower dtype than the inputs (as in
 # equal)
 try:
 np.copyto(result, d, where=m)
 except TypeError:
 pass
 # Transform to
 masked_result = result.view(get_masked_subclass(a))
 masked_result._mask = m
 masked_result._update_from(a)
 return masked_result
class _MaskedBinaryOperation(_MaskedUFunc):
 """
 Define masked version of binary operations, where invalid
 values are pre-masked.
 Parameters
 ----------
 mbfunc : function
 The function for which to define a masked version. Made available
 as ``_MaskedBinaryOperation.f``.
 domain : class instance
 Default domain for the function. Should be one of the ``_Domain*``
 classes. Default is None.
 fillx : scalar, optional
 Filling value for the first argument, default is 0.
 filly : scalar, optional
 Filling value for the second argument, default is 0.
 """
def __init__(self, mbfunc, fillx=0, filly=0):
 """
 abfunc(fillx, filly) must be defined.
 abfunc(x, filly) = x for all x to enable reduce.
 """
 super().__init__(mbfunc)
 self.fillx = fillx
 self.filly = filly
 ufunc_domain[mbfunc] = None
 ufunc_fills[mbfunc] = (fillx, filly)
def __call__(self, a, b, *args, **kwargs):
 """
 Execute the call behavior.
 """
 # Get the data, as ndarray
 (da, db) = (getdata(a), getdata(b))
 # Get the result
 with np.errstate():
 np.seterr(divide='ignore', invalid='ignore')
 result = self.f(da, db, *args, **kwargs)
 # Get the mask for the result
 (ma, mb) = (getmask(a), getmask(b))
 if ma is nomask:
 if mb is nomask:
 m = nomask
 else:
 m = umath.logical_or(getmaskarray(a), mb)
 elif mb is nomask:
 m = umath.logical_or(ma, getmaskarray(b))
 else:
 m = umath.logical_or(ma, mb)
# Case 1. : scalar
 if not result.ndim:
 if m:
 return masked
 return result
# Case 2. : array
 # Revert result to da where masked
 if m is not nomask and m.any():
 # any errors, just abort; impossible to guarantee masked values
 try:
 np.copyto(result, da, casting='unsafe', where=m)
 except Exception:
 pass
# Transforms to a (subclass of) MaskedArray
 masked_result = result.view(get_masked_subclass(a, b))
 masked_result._mask = m
 if isinstance(a, MaskedArray):
 masked_result._update_from(a)
 elif isinstance(b, MaskedArray):
 masked_result._update_from(b)
 return masked_result
def reduce(self, target, axis=0, dtype=None):
 """
 Reduce `target` along the given `axis`.
 """
 tclass = get_masked_subclass(target)
 m = getmask(target)
 t = filled(target, self.filly)
 if t.shape == ():
 t = t.reshape(1)
 if m is not nomask:
 m = make_mask(m, copy=True)
 m.shape = (1,)
if m is nomask:
 tr = self.f.reduce(t, axis)
 mr = nomask
 else:
 tr = self.f.reduce(t, axis, dtype=dtype)
 mr = umath.logical_and.reduce(m, axis)
if not tr.shape:
 if mr:
 return masked
 else:
 return tr
 masked_tr = tr.view(tclass)
 masked_tr._mask = mr
 return masked_tr
def outer(self, a, b):
 """
 Return the function applied to the outer product of a and b.
 """
 (da, db) = (getdata(a), getdata(b))
 d = self.f.outer(da, db)
 ma = getmask(a)
 mb = getmask(b)
 if ma is nomask and mb is nomask:
 m = nomask
 else:
 ma = getmaskarray(a)
 mb = getmaskarray(b)
 m = umath.logical_or.outer(ma, mb)
 if (not m.ndim) and m:
 return masked
 if m is not nomask:
 np.copyto(d, da, where=m)
 if not d.shape:
 return d
 masked_d = d.view(get_masked_subclass(a, b))
 masked_d._mask = m
 return masked_d
def accumulate(self, target, axis=0):
 """Accumulate `target` along `axis` after filling with y fill
 value.
 """
 tclass = get_masked_subclass(target)
 t = filled(target, self.filly)
 result = self.f.accumulate(t, axis)
 masked_result = result.view(tclass)
 return masked_result
class _DomainedBinaryOperation(_MaskedUFunc):
 """
 Define binary operations that have a domain, like divide.
 They have no reduce, outer or accumulate.
 Parameters
 ----------
 mbfunc : function
 The function for which to define a masked version. Made available
 as ``_DomainedBinaryOperation.f``.
 domain : class instance
 Default domain for the function. Should be one of the ``_Domain*``
 classes.
 fillx : scalar, optional
 Filling value for the first argument, default is 0.
 filly : scalar, optional
 Filling value for the second argument, default is 0.
 """
def __init__(self, dbfunc, domain, fillx=0, filly=0):
 """abfunc(fillx, filly) must be defined.
 abfunc(x, filly) = x for all x to enable reduce.
 """
 super().__init__(dbfunc)
 self.domain = domain
 self.fillx = fillx
 self.filly = filly
 ufunc_domain[dbfunc] = domain
 ufunc_fills[dbfunc] = (fillx, filly)
def __call__(self, a, b, *args, **kwargs):
 "Execute the call behavior."
 # Get the data
 (da, db) = (getdata(a), getdata(b))
 # Get the result
 with np.errstate(divide='ignore', invalid='ignore'):
 result = self.f(da, db, *args, **kwargs)
 # Get the mask as a combination of the source masks and invalid
 m = ~umath.isfinite(result)
 m |= getmask(a)
 m |= getmask(b)
 # Apply the domain
 domain = ufunc_domain.get(self.f, None)
 if domain is not None:
 m |= domain(da, db)
 # Take care of the scalar case first
 if not m.ndim:
 if m:
 return masked
 else:
 return result
 # When the mask is True, put back da if possible
 # any errors, just abort; impossible to guarantee masked values
 try:
 np.copyto(result, 0, casting='unsafe', where=m)
 # avoid using "*" since this may be overlaid
 masked_da = umath.multiply(m, da)
 # only add back if it can be cast safely
 if np.can_cast(masked_da.dtype, result.dtype, casting='safe'):
 result += masked_da
 except Exception:
 pass
# Transforms to a (subclass of) MaskedArray
 masked_result = result.view(get_masked_subclass(a, b))
 masked_result._mask = m
 if isinstance(a, MaskedArray):
 masked_result._update_from(a)
 elif isinstance(b, MaskedArray):
 masked_result._update_from(b)
 return masked_result
# Unary ufuncs
exp = _MaskedUnaryOperation(umath.exp)
conjugate = _MaskedUnaryOperation(umath.conjugate)
sin = _MaskedUnaryOperation(umath.sin)
cos = _MaskedUnaryOperation(umath.cos)
arctan = _MaskedUnaryOperation(umath.arctan)
arcsinh = _MaskedUnaryOperation(umath.arcsinh)
sinh = _MaskedUnaryOperation(umath.sinh)
cosh = _MaskedUnaryOperation(umath.cosh)
tanh = _MaskedUnaryOperation(umath.tanh)
abs = absolute = _MaskedUnaryOperation(umath.absolute)
angle = _MaskedUnaryOperation(angle)
fabs = _MaskedUnaryOperation(umath.fabs)
negative = _MaskedUnaryOperation(umath.negative)
floor = _MaskedUnaryOperation(umath.floor)
ceil = _MaskedUnaryOperation(umath.ceil)
around = _MaskedUnaryOperation(np.around)
logical_not = _MaskedUnaryOperation(umath.logical_not)
# Domained unary ufuncs
sqrt = _MaskedUnaryOperation(umath.sqrt, 0.0,
 _DomainGreaterEqual(0.0))
log = _MaskedUnaryOperation(umath.log, 1.0,
 _DomainGreater(0.0))
log2 = _MaskedUnaryOperation(umath.log2, 1.0,
 _DomainGreater(0.0))
log10 = _MaskedUnaryOperation(umath.log10, 1.0,
 _DomainGreater(0.0))
tan = _MaskedUnaryOperation(umath.tan, 0.0,
 _DomainTan(1e-35))
arcsin = _MaskedUnaryOperation(umath.arcsin, 0.0,
 _DomainCheckInterval(-1.0, 1.0))
arccos = _MaskedUnaryOperation(umath.arccos, 0.0,
 _DomainCheckInterval(-1.0, 1.0))
arccosh = _MaskedUnaryOperation(umath.arccosh, 1.0,
 _DomainGreaterEqual(1.0))
arctanh = _MaskedUnaryOperation(umath.arctanh, 0.0,
 _DomainCheckInterval(-1.0 + 1e-15, 1.0 - 1e-15))
# Binary ufuncs
add = _MaskedBinaryOperation(umath.add)
subtract = _MaskedBinaryOperation(umath.subtract)
multiply = _MaskedBinaryOperation(umath.multiply, 1, 1)
arctan2 = _MaskedBinaryOperation(umath.arctan2, 0.0, 1.0)
equal = _MaskedBinaryOperation(umath.equal)
equal.reduce = None
not_equal = _MaskedBinaryOperation(umath.not_equal)
not_equal.reduce = None
less_equal = _MaskedBinaryOperation(umath.less_equal)
less_equal.reduce = None
greater_equal = _MaskedBinaryOperation(umath.greater_equal)
greater_equal.reduce = None
less = _MaskedBinaryOperation(umath.less)
less.reduce = None
greater = _MaskedBinaryOperation(umath.greater)
greater.reduce = None
logical_and = _MaskedBinaryOperation(umath.logical_and)
alltrue = _MaskedBinaryOperation(umath.logical_and, 1, 1).reduce
logical_or = _MaskedBinaryOperation(umath.logical_or)
sometrue = logical_or.reduce
logical_xor = _MaskedBinaryOperation(umath.logical_xor)
bitwise_and = _MaskedBinaryOperation(umath.bitwise_and)
bitwise_or = _MaskedBinaryOperation(umath.bitwise_or)
bitwise_xor = _MaskedBinaryOperation(umath.bitwise_xor)
hypot = _MaskedBinaryOperation(umath.hypot)
# Domained binary ufuncs
divide = _DomainedBinaryOperation(umath.divide, _DomainSafeDivide(), 0, 1)
true_divide = divide # Just an alias for divide.
floor_divide = _DomainedBinaryOperation(umath.floor_divide,
 _DomainSafeDivide(), 0, 1)
remainder = _DomainedBinaryOperation(umath.remainder,
 _DomainSafeDivide(), 0, 1)
fmod = _DomainedBinaryOperation(umath.fmod, _DomainSafeDivide(), 0, 1)
mod = remainder
###############################################################################
# Mask creation functions #
###############################################################################
def _replace_dtype_fields_recursive(dtype, primitive_dtype):
 "Private function allowing recursion in _replace_dtype_fields."
 _recurse = _replace_dtype_fields_recursive
# Do we have some name fields ?
 if dtype.names is not None:
 descr = []
 for name in dtype.names:
 field = dtype.fields[name]
 if len(field) == 3:
 # Prepend the title to the name
 name = (field[-1], name)
 descr.append((name, _recurse(field[0], primitive_dtype)))
 new_dtype = np.dtype(descr)
# Is this some kind of composite a la (float,2)
 elif dtype.subdtype:
 descr = list(dtype.subdtype)
 descr[0] = _recurse(dtype.subdtype[0], primitive_dtype)
 new_dtype = np.dtype(tuple(descr))
# this is a primitive type, so do a direct replacement
 else:
 new_dtype = primitive_dtype
# preserve identity of dtypes
 if new_dtype == dtype:
 new_dtype = dtype
return new_dtype
def _replace_dtype_fields(dtype, primitive_dtype):
 """
 Construct a dtype description list from a given dtype.
 Returns a new dtype object, with all fields and subtypes in the given type
 recursively replaced with `primitive_dtype`.
 Arguments are coerced to dtypes first.
 """
 dtype = np.dtype(dtype)
 primitive_dtype = np.dtype(primitive_dtype)
 return _replace_dtype_fields_recursive(dtype, primitive_dtype)
def make_mask_descr(ndtype):
 """
 Construct a dtype description list from a given dtype.
 Returns a new dtype object, with the type of all fields in `ndtype` to a
 boolean type. Field names are not altered.
 Parameters
 ----------
 ndtype : dtype
 The dtype to convert.
 Returns
 -------
 result : dtype
 A dtype that looks like `ndtype`, the type of all fields is boolean.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> dtype = np.dtype({'names':['foo', 'bar'],
 ... 'formats':[np.float32, np.int64]})
 >>> dtype
 dtype([('foo', '<f4'), ('bar', '<i8')])
 >>> ma.make_mask_descr(dtype)
 dtype([('foo', '|b1'), ('bar', '|b1')])
 >>> ma.make_mask_descr(np.float32)
 dtype('bool')
 """
 return _replace_dtype_fields(ndtype, MaskType)
def getmask(a):
 """
 Return the mask of a masked array, or nomask.
 Return the mask of `a` as an ndarray if `a` is a `MaskedArray` and the
 mask is not `nomask`, else return `nomask`. To guarantee a full array
 of booleans of the same shape as a, use `getmaskarray`.
 Parameters
 ----------
 a : array_like
 Input `MaskedArray` for which the mask is required.
 See Also
 --------
 getdata : Return the data of a masked array as an ndarray.
 getmaskarray : Return the mask of a masked array, or full array of False.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = ma.masked_equal([[1,2],[3,4]], 2)
 >>> a
 masked_array(
 data=[[1, --],
 [3, 4]],
 mask=[[False, True],
 [False, False]],
 fill_value=2)
 >>> ma.getmask(a)
 array([[False, True],
 [False, False]])
 Equivalently use the `MaskedArray` `mask` attribute.
 >>> a.mask
 array([[False, True],
 [False, False]])
 Result when mask == `nomask`
 >>> b = ma.masked_array([[1,2],[3,4]])
 >>> b
 masked_array(
 data=[[1, 2],
 [3, 4]],
 mask=False,
 fill_value=999999)
 >>> ma.nomask
 False
 >>> ma.getmask(b) == ma.nomask
 True
 >>> b.mask == ma.nomask
 True
 """
 return getattr(a, '_mask', nomask)
get_mask = getmask
def getmaskarray(arr):
 """
 Return the mask of a masked array, or full boolean array of False.
 Return the mask of `arr` as an ndarray if `arr` is a `MaskedArray` and
 the mask is not `nomask`, else return a full boolean array of False of
 the same shape as `arr`.
 Parameters
 ----------
 arr : array_like
 Input `MaskedArray` for which the mask is required.
 See Also
 --------
 getmask : Return the mask of a masked array, or nomask.
 getdata : Return the data of a masked array as an ndarray.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = ma.masked_equal([[1,2],[3,4]], 2)
 >>> a
 masked_array(
 data=[[1, --],
 [3, 4]],
 mask=[[False, True],
 [False, False]],
 fill_value=2)
 >>> ma.getmaskarray(a)
 array([[False, True],
 [False, False]])
 Result when mask == ``nomask``
 >>> b = ma.masked_array([[1,2],[3,4]])
 >>> b
 masked_array(
 data=[[1, 2],
 [3, 4]],
 mask=False,
 fill_value=999999)
 >>> ma.getmaskarray(b)
 array([[False, False],
 [False, False]])
 """
 mask = getmask(arr)
 if mask is nomask:
 mask = make_mask_none(np.shape(arr), getattr(arr, 'dtype', None))
 return mask
def is_mask(m):
 """
 Return True if m is a valid, standard mask.
 This function does not check the contents of the input, only that the
 type is MaskType. In particular, this function returns False if the
 mask has a flexible dtype.
 Parameters
 ----------
 m : array_like
 Array to test.
 Returns
 -------
 result : bool
 True if `m.dtype.type` is MaskType, False otherwise.
 See Also
 --------
 ma.isMaskedArray : Test whether input is an instance of MaskedArray.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> m = ma.masked_equal([0, 1, 0, 2, 3], 0)
 >>> m
 masked_array(data=[--, 1, --, 2, 3],
 mask=[ True, False, True, False, False],
 fill_value=0)
 >>> ma.is_mask(m)
 False
 >>> ma.is_mask(m.mask)
 True
 Input must be an ndarray (or have similar attributes)
 for it to be considered a valid mask.
 >>> m = [False, True, False]
 >>> ma.is_mask(m)
 False
 >>> m = np.array([False, True, False])
 >>> m
 array([False, True, False])
 >>> ma.is_mask(m)
 True
 Arrays with complex dtypes don't return True.
 >>> dtype = np.dtype({'names':['monty', 'pithon'],
 ... 'formats':[bool, bool]})
 >>> dtype
 dtype([('monty', '|b1'), ('pithon', '|b1')])
 >>> m = np.array([(True, False), (False, True), (True, False)],
 ... dtype=dtype)
 >>> m
 array([( True, False), (False, True), ( True, False)],
 dtype=[('monty', '?'), ('pithon', '?')])
 >>> ma.is_mask(m)
 False
 """
 try:
 return m.dtype.type is MaskType
 except AttributeError:
 return False
def _shrink_mask(m):
 """
 Shrink a mask to nomask if possible
 """
 if m.dtype.names is None and not m.any():
 return nomask
 else:
 return m
def make_mask(m, copy=False, shrink=True, dtype=MaskType):
 """
 Create a boolean mask from an array.
 Return `m` as a boolean mask, creating a copy if necessary or requested.
 The function can accept any sequence that is convertible to integers,
 or ``nomask``. Does not require that contents must be 0s and 1s, values
 of 0 are interpreted as False, everything else as True.
 Parameters
 ----------
 m : array_like
 Potential mask.
 copy : bool, optional
 Whether to return a copy of `m` (True) or `m` itself (False).
 shrink : bool, optional
 Whether to shrink `m` to ``nomask`` if all its values are False.
 dtype : dtype, optional
 Data-type of the output mask. By default, the output mask has a
 dtype of MaskType (bool). If the dtype is flexible, each field has
 a boolean dtype. This is ignored when `m` is ``nomask``, in which
 case ``nomask`` is always returned.
 Returns
 -------
 result : ndarray
 A boolean mask derived from `m`.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> m = [True, False, True, True]
 >>> ma.make_mask(m)
 array([ True, False, True, True])
 >>> m = [1, 0, 1, 1]
 >>> ma.make_mask(m)
 array([ True, False, True, True])
 >>> m = [1, 0, 2, -3]
 >>> ma.make_mask(m)
 array([ True, False, True, True])
 Effect of the `shrink` parameter.
 >>> m = np.zeros(4)
 >>> m
 array([0., 0., 0., 0.])
 >>> ma.make_mask(m)
 False
 >>> ma.make_mask(m, shrink=False)
 array([False, False, False, False])
 Using a flexible `dtype`.
 >>> m = [1, 0, 1, 1]
 >>> n = [0, 1, 0, 0]
 >>> arr = []
 >>> for man, mouse in zip(m, n):
 ... arr.append((man, mouse))
 >>> arr
 [(1, 0), (0, 1), (1, 0), (1, 0)]
 >>> dtype = np.dtype({'names':['man', 'mouse'],
 ... 'formats':[np.int64, np.int64]})
 >>> arr = np.array(arr, dtype=dtype)
 >>> arr
 array([(1, 0), (0, 1), (1, 0), (1, 0)],
 dtype=[('man', '<i8'), ('mouse', '<i8')])
 >>> ma.make_mask(arr, dtype=dtype)
 array([(True, False), (False, True), (True, False), (True, False)],
 dtype=[('man', '|b1'), ('mouse', '|b1')])
 """
 if m is nomask:
 return nomask
# Make sure the input dtype is valid.
 dtype = make_mask_descr(dtype)
# legacy boolean special case: "existence of fields implies true"
 if isinstance(m, ndarray) and m.dtype.fields and dtype == np.bool:
 return np.ones(m.shape, dtype=dtype)
# Fill the mask in case there are missing data; turn it into an ndarray.
 copy = None if not copy else True
 result = np.array(filled(m, True), copy=copy, dtype=dtype, subok=True)
 # Bas les masques !
 if shrink:
 result = _shrink_mask(result)
 return result
def make_mask_none(newshape, dtype=None):
 """
 Return a boolean mask of the given shape, filled with False.
 This function returns a boolean ndarray with all entries False, that can
 be used in common mask manipulations. If a complex dtype is specified, the
 type of each field is converted to a boolean type.
 Parameters
 ----------
 newshape : tuple
 A tuple indicating the shape of the mask.
 dtype : {None, dtype}, optional
 If None, use a MaskType instance. Otherwise, use a new datatype with
 the same fields as `dtype`, converted to boolean types.
 Returns
 -------
 result : ndarray
 An ndarray of appropriate shape and dtype, filled with False.
 See Also
 --------
 make_mask : Create a boolean mask from an array.
 make_mask_descr : Construct a dtype description list from a given dtype.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> ma.make_mask_none((3,))
 array([False, False, False])
 Defining a more complex dtype.
 >>> dtype = np.dtype({'names':['foo', 'bar'],
 ... 'formats':[np.float32, np.int64]})
 >>> dtype
 dtype([('foo', '<f4'), ('bar', '<i8')])
 >>> ma.make_mask_none((3,), dtype=dtype)
 array([(False, False), (False, False), (False, False)],
 dtype=[('foo', '|b1'), ('bar', '|b1')])
 """
 if dtype is None:
 result = np.zeros(newshape, dtype=MaskType)
 else:
 result = np.zeros(newshape, dtype=make_mask_descr(dtype))
 return result
def _recursive_mask_or(m1, m2, newmask):
 names = m1.dtype.names
 for name in names:
 current1 = m1[name]
 if current1.dtype.names is not None:
 _recursive_mask_or(current1, m2[name], newmask[name])
 else:
 umath.logical_or(current1, m2[name], newmask[name])
def mask_or(m1, m2, copy=False, shrink=True):
 """
 Combine two masks with the ``logical_or`` operator.
 The result may be a view on `m1` or `m2` if the other is `nomask`
 (i.e. False).
 Parameters
 ----------
 m1, m2 : array_like
 Input masks.
 copy : bool, optional
 If copy is False and one of the inputs is `nomask`, return a view
 of the other input mask. Defaults to False.
 shrink : bool, optional
 Whether to shrink the output to `nomask` if all its values are
 False. Defaults to True.
 Returns
 -------
 mask : output mask
 The result masks values that are masked in either `m1` or `m2`.
 Raises
 ------
 ValueError
 If `m1` and `m2` have different flexible dtypes.
 Examples
 --------
 >>> import numpy as np
 >>> m1 = np.ma.make_mask([0, 1, 1, 0])
 >>> m2 = np.ma.make_mask([1, 0, 0, 0])
 >>> np.ma.mask_or(m1, m2)
 array([ True, True, True, False])
 """
if (m1 is nomask) or (m1 is False):
 dtype = getattr(m2, 'dtype', MaskType)
 return make_mask(m2, copy=copy, shrink=shrink, dtype=dtype)
 if (m2 is nomask) or (m2 is False):
 dtype = getattr(m1, 'dtype', MaskType)
 return make_mask(m1, copy=copy, shrink=shrink, dtype=dtype)
 if m1 is m2 and is_mask(m1):
 return _shrink_mask(m1) if shrink else m1
 (dtype1, dtype2) = (getattr(m1, 'dtype', None), getattr(m2, 'dtype', None))
 if dtype1 != dtype2:
 raise ValueError(f"Incompatible dtypes '{dtype1}'<>'{dtype2}'")
 if dtype1.names is not None:
 # Allocate an output mask array with the properly broadcast shape.
 newmask = np.empty(np.broadcast(m1, m2).shape, dtype1)
 _recursive_mask_or(m1, m2, newmask)
 return newmask
 return make_mask(umath.logical_or(m1, m2), copy=copy, shrink=shrink)
def flatten_mask(mask):
 """
 Returns a completely flattened version of the mask, where nested fields
 are collapsed.
 Parameters
 ----------
 mask : array_like
 Input array, which will be interpreted as booleans.
 Returns
 -------
 flattened_mask : ndarray of bools
 The flattened input.
 Examples
 --------
 >>> import numpy as np
 >>> mask = np.array([0, 0, 1])
 >>> np.ma.flatten_mask(mask)
 array([False, False, True])
 >>> mask = np.array([(0, 0), (0, 1)], dtype=[('a', bool), ('b', bool)])
 >>> np.ma.flatten_mask(mask)
 array([False, False, False, True])
 >>> mdtype = [('a', bool), ('b', [('ba', bool), ('bb', bool)])]
 >>> mask = np.array([(0, (0, 0)), (0, (0, 1))], dtype=mdtype)
 >>> np.ma.flatten_mask(mask)
 array([False, False, False, False, False, True])
 """
def _flatmask(mask):
 "Flatten the mask and returns a (maybe nested) sequence of booleans."
 mnames = mask.dtype.names
 if mnames is not None:
 return [flatten_mask(mask[name]) for name in mnames]
 else:
 return mask
def _flatsequence(sequence):
 "Generates a flattened version of the sequence."
 try:
 for element in sequence:
 if hasattr(element, '__iter__'):
 yield from _flatsequence(element)
 else:
 yield element
 except TypeError:
 yield sequence
mask = np.asarray(mask)
 flattened = _flatsequence(_flatmask(mask))
 return np.array(list(flattened), dtype=bool)
def _check_mask_axis(mask, axis, keepdims=np._NoValue):
 "Check whether there are masked values along the given axis"
 kwargs = {} if keepdims is np._NoValue else {'keepdims': keepdims}
 if mask is not nomask:
 return mask.all(axis=axis, **kwargs)
 return nomask
###############################################################################
# Masking functions #
###############################################################################
def masked_where(condition, a, copy=True):
 """
 Mask an array where a condition is met.
 Return `a` as an array masked where `condition` is True.
 Any masked values of `a` or `condition` are also masked in the output.
 Parameters
 ----------
 condition : array_like
 Masking condition. When `condition` tests floating point values for
 equality, consider using ``masked_values`` instead.
 a : array_like
 Array to mask.
 copy : bool
 If True (default) make a copy of `a` in the result. If False modify
 `a` in place and return a view.
 Returns
 -------
 result : MaskedArray
 The result of masking `a` where `condition` is True.
 See Also
 --------
 masked_values : Mask using floating point equality.
 masked_equal : Mask where equal to a given value.
 masked_not_equal : Mask where *not* equal to a given value.
 masked_less_equal : Mask where less than or equal to a given value.
 masked_greater_equal : Mask where greater than or equal to a given value.
 masked_less : Mask where less than a given value.
 masked_greater : Mask where greater than a given value.
 masked_inside : Mask inside a given interval.
 masked_outside : Mask outside a given interval.
 masked_invalid : Mask invalid values (NaNs or infs).
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = np.arange(4)
 >>> a
 array([0, 1, 2, 3])
 >>> ma.masked_where(a <= 2, a)
 masked_array(data=[--, --, --, 3],
 mask=[ True, True, True, False],
 fill_value=999999)
 Mask array `b` conditional on `a`.
 >>> b = ['a', 'b', 'c', 'd']
 >>> ma.masked_where(a == 2, b)
 masked_array(data=['a', 'b', --, 'd'],
 mask=[False, False, True, False],
 fill_value='N/A',
 dtype='<U1')
 Effect of the `copy` argument.
 >>> c = ma.masked_where(a <= 2, a)
 >>> c
 masked_array(data=[--, --, --, 3],
 mask=[ True, True, True, False],
 fill_value=999999)
 >>> c[0] = 99
 >>> c
 masked_array(data=[99, --, --, 3],
 mask=[False, True, True, False],
 fill_value=999999)
 >>> a
 array([0, 1, 2, 3])
 >>> c = ma.masked_where(a <= 2, a, copy=False)
 >>> c[0] = 99
 >>> c
 masked_array(data=[99, --, --, 3],
 mask=[False, True, True, False],
 fill_value=999999)
 >>> a
 array([99, 1, 2, 3])
 When `condition` or `a` contain masked values.
 >>> a = np.arange(4)
 >>> a = ma.masked_where(a == 2, a)
 >>> a
 masked_array(data=[0, 1, --, 3],
 mask=[False, False, True, False],
 fill_value=999999)
 >>> b = np.arange(4)
 >>> b = ma.masked_where(b == 0, b)
 >>> b
 masked_array(data=[--, 1, 2, 3],
 mask=[ True, False, False, False],
 fill_value=999999)
 >>> ma.masked_where(a == 3, b)
 masked_array(data=[--, 1, --, --],
 mask=[ True, False, True, True],
 fill_value=999999)
 """
 # Make sure that condition is a valid standard-type mask.
 cond = make_mask(condition, shrink=False)
 a = np.array(a, copy=copy, subok=True)
(cshape, ashape) = (cond.shape, a.shape)
 if cshape and cshape != ashape:
 raise IndexError("Inconsistent shape between the condition and the input"
 " (got %s and %s)" % (cshape, ashape))
 if hasattr(a, '_mask'):
 cond = mask_or(cond, a._mask)
 cls = type(a)
 else:
 cls = MaskedArray
 result = a.view(cls)
 # Assign to *.mask so that structured masks are handled correctly.
 result.mask = _shrink_mask(cond)
 # There is no view of a boolean so when 'a' is a MaskedArray with nomask
 # the update to the result's mask has no effect.
 if not copy and hasattr(a, '_mask') and getmask(a) is nomask:
 a._mask = result._mask.view()
 return result
def masked_greater(x, value, copy=True):
 """
 Mask an array where greater than a given value.
 This function is a shortcut to ``masked_where``, with
 `condition` = (x > value).
 See Also
 --------
 masked_where : Mask where a condition is met.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = np.arange(4)
 >>> a
 array([0, 1, 2, 3])
 >>> ma.masked_greater(a, 2)
 masked_array(data=[0, 1, 2, --],
 mask=[False, False, False, True],
 fill_value=999999)
 """
 return masked_where(greater(x, value), x, copy=copy)
def masked_greater_equal(x, value, copy=True):
 """
 Mask an array where greater than or equal to a given value.
 This function is a shortcut to ``masked_where``, with
 `condition` = (x >= value).
 See Also
 --------
 masked_where : Mask where a condition is met.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = np.arange(4)
 >>> a
 array([0, 1, 2, 3])
 >>> ma.masked_greater_equal(a, 2)
 masked_array(data=[0, 1, --, --],
 mask=[False, False, True, True],
 fill_value=999999)
 """
 return masked_where(greater_equal(x, value), x, copy=copy)
def masked_less(x, value, copy=True):
 """
 Mask an array where less than a given value.
 This function is a shortcut to ``masked_where``, with
 `condition` = (x < value).
 See Also
 --------
 masked_where : Mask where a condition is met.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = np.arange(4)
 >>> a
 array([0, 1, 2, 3])
 >>> ma.masked_less(a, 2)
 masked_array(data=[--, --, 2, 3],
 mask=[ True, True, False, False],
 fill_value=999999)
 """
 return masked_where(less(x, value), x, copy=copy)
def masked_less_equal(x, value, copy=True):
 """
 Mask an array where less than or equal to a given value.
 This function is a shortcut to ``masked_where``, with
 `condition` = (x <= value).
 See Also
 --------
 masked_where : Mask where a condition is met.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = np.arange(4)
 >>> a
 array([0, 1, 2, 3])
 >>> ma.masked_less_equal(a, 2)
 masked_array(data=[--, --, --, 3],
 mask=[ True, True, True, False],
 fill_value=999999)
 """
 return masked_where(less_equal(x, value), x, copy=copy)
def masked_not_equal(x, value, copy=True):
 """
 Mask an array where *not* equal to a given value.
 This function is a shortcut to ``masked_where``, with
 `condition` = (x != value).
 See Also
 --------
 masked_where : Mask where a condition is met.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = np.arange(4)
 >>> a
 array([0, 1, 2, 3])
 >>> ma.masked_not_equal(a, 2)
 masked_array(data=[--, --, 2, --],
 mask=[ True, True, False, True],
 fill_value=999999)
 """
 return masked_where(not_equal(x, value), x, copy=copy)
def masked_equal(x, value, copy=True):
 """
 Mask an array where equal to a given value.
 Return a MaskedArray, masked where the data in array `x` are
 equal to `value`. The fill_value of the returned MaskedArray
 is set to `value`.
 For floating point arrays, consider using ``masked_values(x, value)``.
 See Also
 --------
 masked_where : Mask where a condition is met.
 masked_values : Mask using floating point equality.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = np.arange(4)
 >>> a
 array([0, 1, 2, 3])
 >>> ma.masked_equal(a, 2)
 masked_array(data=[0, 1, --, 3],
 mask=[False, False, True, False],
 fill_value=2)
 """
 output = masked_where(equal(x, value), x, copy=copy)
 output.fill_value = value
 return output
def masked_inside(x, v1, v2, copy=True):
 """
 Mask an array inside a given interval.
 Shortcut to ``masked_where``, where `condition` is True for `x` inside
 the interval [v1,v2] (v1 <= x <= v2). The boundaries `v1` and `v2`
 can be given in either order.
 See Also
 --------
 masked_where : Mask where a condition is met.
 Notes
 -----
 The array `x` is prefilled with its filling value.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> x = [0.31, 1.2, 0.01, 0.2, -0.4, -1.1]
 >>> ma.masked_inside(x, -0.3, 0.3)
 masked_array(data=[0.31, 1.2, --, --, -0.4, -1.1],
 mask=[False, False, True, True, False, False],
 fill_value=1e+20)
 The order of `v1` and `v2` doesn't matter.
 >>> ma.masked_inside(x, 0.3, -0.3)
 masked_array(data=[0.31, 1.2, --, --, -0.4, -1.1],
 mask=[False, False, True, True, False, False],
 fill_value=1e+20)
 """
 if v2 < v1:
 (v1, v2) = (v2, v1)
 xf = filled(x)
 condition = (xf >= v1) & (xf <= v2)
 return masked_where(condition, x, copy=copy)
def masked_outside(x, v1, v2, copy=True):
 """
 Mask an array outside a given interval.
 Shortcut to ``masked_where``, where `condition` is True for `x` outside
 the interval [v1,v2] (x < v1)|(x > v2).
 The boundaries `v1` and `v2` can be given in either order.
 See Also
 --------
 masked_where : Mask where a condition is met.
 Notes
 -----
 The array `x` is prefilled with its filling value.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> x = [0.31, 1.2, 0.01, 0.2, -0.4, -1.1]
 >>> ma.masked_outside(x, -0.3, 0.3)
 masked_array(data=[--, --, 0.01, 0.2, --, --],
 mask=[ True, True, False, False, True, True],
 fill_value=1e+20)
 The order of `v1` and `v2` doesn't matter.
 >>> ma.masked_outside(x, 0.3, -0.3)
 masked_array(data=[--, --, 0.01, 0.2, --, --],
 mask=[ True, True, False, False, True, True],
 fill_value=1e+20)
 """
 if v2 < v1:
 (v1, v2) = (v2, v1)
 xf = filled(x)
 condition = (xf < v1) | (xf > v2)
 return masked_where(condition, x, copy=copy)
def masked_object(x, value, copy=True, shrink=True):
 """
 Mask the array `x` where the data are exactly equal to value.
 This function is similar to `masked_values`, but only suitable
 for object arrays: for floating point, use `masked_values` instead.
 Parameters
 ----------
 x : array_like
 Array to mask
 value : object
 Comparison value
 copy : {True, False}, optional
 Whether to return a copy of `x`.
 shrink : {True, False}, optional
 Whether to collapse a mask full of False to nomask
 Returns
 -------
 result : MaskedArray
 The result of masking `x` where equal to `value`.
 See Also
 --------
 masked_where : Mask where a condition is met.
 masked_equal : Mask where equal to a given value (integers).
 masked_values : Mask using floating point equality.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> food = np.array(['green_eggs', 'ham'], dtype=object)
 >>> # don't eat spoiled food
 >>> eat = ma.masked_object(food, 'green_eggs')
 >>> eat
 masked_array(data=[--, 'ham'],
 mask=[ True, False],
 fill_value='green_eggs',
 dtype=object)
 >>> # plain ol` ham is boring
 >>> fresh_food = np.array(['cheese', 'ham', 'pineapple'], dtype=object)
 >>> eat = ma.masked_object(fresh_food, 'green_eggs')
 >>> eat
 masked_array(data=['cheese', 'ham', 'pineapple'],
 mask=False,
 fill_value='green_eggs',
 dtype=object)
 Note that `mask` is set to ``nomask`` if possible.
 >>> eat
 masked_array(data=['cheese', 'ham', 'pineapple'],
 mask=False,
 fill_value='green_eggs',
 dtype=object)
 """
 if isMaskedArray(x):
 condition = umath.equal(x._data, value)
 mask = x._mask
 else:
 condition = umath.equal(np.asarray(x), value)
 mask = nomask
 mask = mask_or(mask, make_mask(condition, shrink=shrink))
 return masked_array(x, mask=mask, copy=copy, fill_value=value)
def masked_values(x, value, rtol=1e-5, atol=1e-8, copy=True, shrink=True):
 """
 Mask using floating point equality.
 Return a MaskedArray, masked where the data in array `x` are approximately
 equal to `value`, determined using `isclose`. The default tolerances for
 `masked_values` are the same as those for `isclose`.
 For integer types, exact equality is used, in the same way as
 `masked_equal`.
 The fill_value is set to `value` and the mask is set to ``nomask`` if
 possible.
 Parameters
 ----------
 x : array_like
 Array to mask.
 value : float
 Masking value.
 rtol, atol : float, optional
 Tolerance parameters passed on to `isclose`
 copy : bool, optional
 Whether to return a copy of `x`.
 shrink : bool, optional
 Whether to collapse a mask full of False to ``nomask``.
 Returns
 -------
 result : MaskedArray
 The result of masking `x` where approximately equal to `value`.
 See Also
 --------
 masked_where : Mask where a condition is met.
 masked_equal : Mask where equal to a given value (integers).
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> x = np.array([1, 1.1, 2, 1.1, 3])
 >>> ma.masked_values(x, 1.1)
 masked_array(data=[1.0, --, 2.0, --, 3.0],
 mask=[False, True, False, True, False],
 fill_value=1.1)
 Note that `mask` is set to ``nomask`` if possible.
 >>> ma.masked_values(x, 2.1)
 masked_array(data=[1. , 1.1, 2. , 1.1, 3. ],
 mask=False,
 fill_value=2.1)
 Unlike `masked_equal`, `masked_values` can perform approximate equalities.
 >>> ma.masked_values(x, 2.1, atol=1e-1)
 masked_array(data=[1.0, 1.1, --, 1.1, 3.0],
 mask=[False, False, True, False, False],
 fill_value=2.1)
 """
 xnew = filled(x, value)
 if np.issubdtype(xnew.dtype, np.floating):
 mask = np.isclose(xnew, value, atol=atol, rtol=rtol)
 else:
 mask = umath.equal(xnew, value)
 ret = masked_array(xnew, mask=mask, copy=copy, fill_value=value)
 if shrink:
 ret.shrink_mask()
 return ret
def masked_invalid(a, copy=True):
 """
 Mask an array where invalid values occur (NaNs or infs).
 This function is a shortcut to ``masked_where``, with
 `condition` = ~(np.isfinite(a)). Any pre-existing mask is conserved.
 Only applies to arrays with a dtype where NaNs or infs make sense
 (i.e. floating point types), but accepts any array_like object.
 See Also
 --------
 masked_where : Mask where a condition is met.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = np.arange(5, dtype=float)
 >>> a[2] = np.nan
 >>> a[3] = np.inf
 >>> a
 array([ 0., 1., nan, inf, 4.])
 >>> ma.masked_invalid(a)
 masked_array(data=[0.0, 1.0, --, --, 4.0],
 mask=[False, False, True, True, False],
 fill_value=1e+20)
 """
 a = np.array(a, copy=None, subok=True)
 res = masked_where(~(np.isfinite(a)), a, copy=copy)
 # masked_invalid previously never returned nomask as a mask and doing so
 # threw off matplotlib (gh-22842). So use shrink=False:
 if res._mask is nomask:
 res._mask = make_mask_none(res.shape, res.dtype)
 return res
###############################################################################
# Printing options #
###############################################################################
class _MaskedPrintOption:
 """
 Handle the string used to represent missing data in a masked array.
 """
def __init__(self, display):
 """
 Create the masked_print_option object.
 """
 self._display = display
 self._enabled = True
def display(self):
 """
 Display the string to print for masked values.
 """
 return self._display
def set_display(self, s):
 """
 Set the string to print for masked values.
 """
 self._display = s
def enabled(self):
 """
 Is the use of the display value enabled?
 """
 return self._enabled
def enable(self, shrink=1):
 """
 Set the enabling shrink to `shrink`.
 """
 self._enabled = shrink
def __str__(self):
 return str(self._display)
__repr__ = __str__
# if you single index into a masked location you get this object.
masked_print_option = _MaskedPrintOption('--')
def _recursive_printoption(result, mask, printopt):
 """
 Puts printoptions in result where mask is True.
 Private function allowing for recursion
 """
 names = result.dtype.names
 if names is not None:
 for name in names:
 curdata = result[name]
 curmask = mask[name]
 _recursive_printoption(curdata, curmask, printopt)
 else:
 np.copyto(result, printopt, where=mask)
# For better or worse, these end in a newline
_legacy_print_templates = {
 'long_std': textwrap.dedent("""\
 masked_%(name)s(data =
 %(data)s,
 %(nlen)s mask =
 %(mask)s,
 %(nlen)s fill_value = %(fill)s)
 """),
 'long_flx': textwrap.dedent("""\
 masked_%(name)s(data =
 %(data)s,
 %(nlen)s mask =
 %(mask)s,
 %(nlen)s fill_value = %(fill)s,
 %(nlen)s dtype = %(dtype)s)
 """),
 'short_std': textwrap.dedent("""\
 masked_%(name)s(data = %(data)s,
 %(nlen)s mask = %(mask)s,
 %(nlen)s fill_value = %(fill)s)
 """),
 'short_flx': textwrap.dedent("""\
 masked_%(name)s(data = %(data)s,
 %(nlen)s mask = %(mask)s,
 %(nlen)s fill_value = %(fill)s,
 %(nlen)s dtype = %(dtype)s)
 """)
}
###############################################################################
# MaskedArray class #
###############################################################################
def _recursive_filled(a, mask, fill_value):
 """
 Recursively fill `a` with `fill_value`.
 """
 names = a.dtype.names
 for name in names:
 current = a[name]
 if current.dtype.names is not None:
 _recursive_filled(current, mask[name], fill_value[name])
 else:
 np.copyto(current, fill_value[name], where=mask[name])
def flatten_structured_array(a):
 """
 Flatten a structured array.
 The data type of the output is chosen such that it can represent all of the
 (nested) fields.
 Parameters
 ----------
 a : structured array
 Returns
 -------
 output : masked array or ndarray
 A flattened masked array if the input is a masked array, otherwise a
 standard ndarray.
 Examples
 --------
 >>> import numpy as np
 >>> ndtype = [('a', int), ('b', float)]
 >>> a = np.array([(1, 1), (2, 2)], dtype=ndtype)
 >>> np.ma.flatten_structured_array(a)
 array([[1., 1.],
 [2., 2.]])
 """
def flatten_sequence(iterable):
 """
 Flattens a compound of nested iterables.
 """
 for elm in iter(iterable):
 if hasattr(elm, "__iter__") and not isinstance(elm, (str, bytes)):
 yield from flatten_sequence(elm)
 else:
 yield elm
a = np.asanyarray(a)
 inishape = a.shape
 a = a.ravel()
 if isinstance(a, MaskedArray):
 out = np.array([tuple(flatten_sequence(d.item())) for d in a._data])
 out = out.view(MaskedArray)
 out._mask = np.array([tuple(flatten_sequence(d.item()))
 for d in getmaskarray(a)])
 else:
 out = np.array([tuple(flatten_sequence(d.item())) for d in a])
 if len(inishape) > 1:
 newshape = list(out.shape)
 newshape[0] = inishape
 out.shape = tuple(flatten_sequence(newshape))
 return out
def _arraymethod(funcname, onmask=True):
 """
 Return a class method wrapper around a basic array method.
 Creates a class method which returns a masked array, where the new
 ``_data`` array is the output of the corresponding basic method called
 on the original ``_data``.
 If `onmask` is True, the new mask is the output of the method called
 on the initial mask. Otherwise, the new mask is just a reference
 to the initial mask.
 Parameters
 ----------
 funcname : str
 Name of the function to apply on data.
 onmask : bool
 Whether the mask must be processed also (True) or left
 alone (False). Default is True. Make available as `_onmask`
 attribute.
 Returns
 -------
 method : instancemethod
 Class method wrapper of the specified basic array method.
 """
 def wrapped_method(self, *args, **params):
 result = getattr(self._data, funcname)(*args, **params)
 result = result.view(type(self))
 result._update_from(self)
 mask = self._mask
 if not onmask:
 result.__setmask__(mask)
 elif mask is not nomask:
 # __setmask__ makes a copy, which we don't want
 result._mask = getattr(mask, funcname)(*args, **params)
 return result
 methdoc = getattr(ndarray, funcname, None) or getattr(np, funcname, None)
 if methdoc is not None:
 wrapped_method.__doc__ = methdoc.__doc__
 wrapped_method.__name__ = funcname
 return wrapped_method
class MaskedIterator:
 """
 Flat iterator object to iterate over masked arrays.
 A `MaskedIterator` iterator is returned by ``x.flat`` for any masked array
 `x`. It allows iterating over the array as if it were a 1-D array,
 either in a for-loop or by calling its `next` method.
 Iteration is done in C-contiguous style, with the last index varying the
 fastest. The iterator can also be indexed using basic slicing or
 advanced indexing.
 See Also
 --------
 MaskedArray.flat : Return a flat iterator over an array.
 MaskedArray.flatten : Returns a flattened copy of an array.
 Notes
 -----
 `MaskedIterator` is not exported by the `ma` module. Instead of
 instantiating a `MaskedIterator` directly, use `MaskedArray.flat`.
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array(arange(6).reshape(2, 3))
 >>> fl = x.flat
 >>> type(fl)
 <class 'numpy.ma.MaskedIterator'>
 >>> for item in fl:
 ... print(item)
 ...
 0
 1
 2
 3
 4
 5
 Extracting more than a single element b indexing the `MaskedIterator`
 returns a masked array:
 >>> fl[2:4]
 masked_array(data = [2 3],
 mask = False,
 fill_value = 999999)
 """
def __init__(self, ma):
 self.ma = ma
 self.dataiter = ma._data.flat
if ma._mask is nomask:
 self.maskiter = None
 else:
 self.maskiter = ma._mask.flat
def __iter__(self):
 return self
def __getitem__(self, indx):
 result = self.dataiter.__getitem__(indx).view(type(self.ma))
 if self.maskiter is not None:
 _mask = self.maskiter.__getitem__(indx)
 if isinstance(_mask, ndarray):
 # set shape to match that of data; this is needed for matrices
 _mask.shape = result.shape
 result._mask = _mask
 elif isinstance(_mask, np.void):
 return mvoid(result, mask=_mask, hardmask=self.ma._hardmask)
 elif _mask: # Just a scalar, masked
 return masked
 return result
# This won't work if ravel makes a copy
 def __setitem__(self, index, value):
 self.dataiter[index] = getdata(value)
 if self.maskiter is not None:
 self.maskiter[index] = getmaskarray(value)
def __next__(self):
 """
 Return the next value, or raise StopIteration.
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array([3, 2], mask=[0, 1])
 >>> fl = x.flat
 >>> next(fl)
 3
 >>> next(fl)
 masked
 >>> next(fl)
 Traceback (most recent call last):
 ...
 StopIteration
 """
 d = next(self.dataiter)
 if self.maskiter is not None:
 m = next(self.maskiter)
 if isinstance(m, np.void):
 return mvoid(d, mask=m, hardmask=self.ma._hardmask)
 elif m: # Just a scalar, masked
 return masked
 return d
@set_module("numpy.ma")
class MaskedArray(ndarray):
 """
 An array class with possibly masked values.
 Masked values of True exclude the corresponding element from any
 computation.
 Construction::
 x = MaskedArray(data, mask=nomask, dtype=None, copy=False, subok=True,
 ndmin=0, fill_value=None, keep_mask=True, hard_mask=None,
 shrink=True, order=None)
 Parameters
 ----------
 data : array_like
 Input data.
 mask : sequence, optional
 Mask. Must be convertible to an array of booleans with the same
 shape as `data`. True indicates a masked (i.e. invalid) data.
 dtype : dtype, optional
 Data type of the output.
 If `dtype` is None, the type of the data argument (``data.dtype``)
 is used. If `dtype` is not None and different from ``data.dtype``,
 a copy is performed.
 copy : bool, optional
 Whether to copy the input data (True), or to use a reference instead.
 Default is False.
 subok : bool, optional
 Whether to return a subclass of `MaskedArray` if possible (True) or a
 plain `MaskedArray`. Default is True.
 ndmin : int, optional
 Minimum number of dimensions. Default is 0.
 fill_value : scalar, optional
 Value used to fill in the masked values when necessary.
 If None, a default based on the data-type is used.
 keep_mask : bool, optional
 Whether to combine `mask` with the mask of the input data, if any
 (True), or to use only `mask` for the output (False). Default is True.
 hard_mask : bool, optional
 Whether to use a hard mask or not. With a hard mask, masked values
 cannot be unmasked. Default is False.
 shrink : bool, optional
 Whether to force compression of an empty mask. Default is True.
 order : {'C', 'F', 'A'}, optional
 Specify the order of the array. If order is 'C', then the array
 will be in C-contiguous order (last-index varies the fastest).
 If order is 'F', then the returned array will be in
 Fortran-contiguous order (first-index varies the fastest).
 If order is 'A' (default), then the returned array may be
 in any order (either C-, Fortran-contiguous, or even discontiguous),
 unless a copy is required, in which case it will be C-contiguous.
 Examples
 --------
 >>> import numpy as np
 The ``mask`` can be initialized with an array of boolean values
 with the same shape as ``data``.
 >>> data = np.arange(6).reshape((2, 3))
 >>> np.ma.MaskedArray(data, mask=[[False, True, False],
 ... [False, False, True]])
 masked_array(
 data=[[0, --, 2],
 [3, 4, --]],
 mask=[[False, True, False],
 [False, False, True]],
 fill_value=999999)
 Alternatively, the ``mask`` can be initialized to homogeneous boolean
 array with the same shape as ``data`` by passing in a scalar
 boolean value:
 >>> np.ma.MaskedArray(data, mask=False)
 masked_array(
 data=[[0, 1, 2],
 [3, 4, 5]],
 mask=[[False, False, False],
 [False, False, False]],
 fill_value=999999)
 >>> np.ma.MaskedArray(data, mask=True)
 masked_array(
 data=[[--, --, --],
 [--, --, --]],
 mask=[[ True, True, True],
 [ True, True, True]],
 fill_value=999999,
 dtype=int64)
 .. note::
 The recommended practice for initializing ``mask`` with a scalar
 boolean value is to use ``True``/``False`` rather than
 ``np.True_``/``np.False_``. The reason is :attr:`nomask`
 is represented internally as ``np.False_``.
 >>> np.False_ is np.ma.nomask
 True
 """
__array_priority__ = 15
 _defaultmask = nomask
 _defaulthardmask = False
 _baseclass = ndarray
# Maximum number of elements per axis used when printing an array. The
 # 1d case is handled separately because we need more values in this case.
 _print_width = 100
 _print_width_1d = 1500
def __new__(cls, data=None, mask=nomask, dtype=None, copy=False,
 subok=True, ndmin=0, fill_value=None, keep_mask=True,
 hard_mask=None, shrink=True, order=None):
 """
 Create a new masked array from scratch.
 Notes
 -----
 A masked array can also be created by taking a .view(MaskedArray).
 """
 # Process data.
 copy = None if not copy else True
 _data = np.array(data, dtype=dtype, copy=copy,
 order=order, subok=True, ndmin=ndmin)
 _baseclass = getattr(data, '_baseclass', type(_data))
 # Check that we're not erasing the mask.
 if isinstance(data, MaskedArray) and (data.shape != _data.shape):
 copy = True
# Here, we copy the _view_, so that we can attach new properties to it
 # we must never do .view(MaskedConstant), as that would create a new
 # instance of np.ma.masked, which make identity comparison fail
 if isinstance(data, cls) and subok and not isinstance(data, MaskedConstant):
 _data = ndarray.view(_data, type(data))
 else:
 _data = ndarray.view(_data, cls)
# Handle the case where data is not a subclass of ndarray, but
 # still has the _mask attribute like MaskedArrays
 if hasattr(data, '_mask') and not isinstance(data, ndarray):
 _data._mask = data._mask
 # FIXME: should we set `_data._sharedmask = True`?
 # Process mask.
 # Type of the mask
 mdtype = make_mask_descr(_data.dtype)
 if mask is nomask:
 # Case 1. : no mask in input.
 # Erase the current mask ?
 if not keep_mask:
 # With a reduced version
 if shrink:
 _data._mask = nomask
 # With full version
 else:
 _data._mask = np.zeros(_data.shape, dtype=mdtype)
 # Check whether we missed something
 elif isinstance(data, (tuple, list)):
 try:
 # If data is a sequence of masked array
 mask = np.array(
 [getmaskarray(np.asanyarray(m, dtype=_data.dtype))
 for m in data], dtype=mdtype)
 except (ValueError, TypeError):
 # If data is nested
 mask = nomask
 # Force shrinking of the mask if needed (and possible)
 if (mdtype == MaskType) and mask.any():
 _data._mask = mask
 _data._sharedmask = False
 else:
 _data._sharedmask = not copy
 if copy:
 _data._mask = _data._mask.copy()
 # Reset the shape of the original mask
 if getmask(data) is not nomask:
 # gh-21022 encounters an issue here
 # because data._mask.shape is not writeable, but
 # the op was also pointless in that case, because
 # the shapes were the same, so we can at least
 # avoid that path
 if data._mask.shape != data.shape:
 data._mask.shape = data.shape
 else:
 # Case 2. : With a mask in input.
 # If mask is boolean, create an array of True or False
# if users pass `mask=None` be forgiving here and cast it False
 # for speed; although the default is `mask=nomask` and can differ.
 if mask is None:
 mask = False
if mask is True and mdtype == MaskType:
 mask = np.ones(_data.shape, dtype=mdtype)
 elif mask is False and mdtype == MaskType:
 mask = np.zeros(_data.shape, dtype=mdtype)
 else:
 # Read the mask with the current mdtype
 try:
 mask = np.array(mask, copy=copy, dtype=mdtype)
 # Or assume it's a sequence of bool/int
 except TypeError:
 mask = np.array([tuple([m] * len(mdtype)) for m in mask],
 dtype=mdtype)
 # Make sure the mask and the data have the same shape
 if mask.shape != _data.shape:
 (nd, nm) = (_data.size, mask.size)
 if nm == 1:
 mask = np.resize(mask, _data.shape)
 elif nm == nd:
 mask = np.reshape(mask, _data.shape)
 else:
 msg = (f"Mask and data not compatible:"
 f" data size is {nd}, mask size is {nm}.")
 raise MaskError(msg)
 copy = True
 # Set the mask to the new value
 if _data._mask is nomask:
 _data._mask = mask
 _data._sharedmask = not copy
 elif not keep_mask:
 _data._mask = mask
 _data._sharedmask = not copy
 else:
 if _data.dtype.names is not None:
 def _recursive_or(a, b):
 "do a|=b on each field of a, recursively"
 for name in a.dtype.names:
 (af, bf) = (a[name], b[name])
 if af.dtype.names is not None:
 _recursive_or(af, bf)
 else:
 af |= bf
_recursive_or(_data._mask, mask)
 else:
 _data._mask = np.logical_or(mask, _data._mask)
 _data._sharedmask = False
# Update fill_value.
 if fill_value is None:
 fill_value = getattr(data, '_fill_value', None)
 # But don't run the check unless we have something to check.
 if fill_value is not None:
 _data._fill_value = _check_fill_value(fill_value, _data.dtype)
 # Process extra options ..
 if hard_mask is None:
 _data._hardmask = getattr(data, '_hardmask', False)
 else:
 _data._hardmask = hard_mask
 _data._baseclass = _baseclass
 return _data
def _update_from(self, obj):
 """
 Copies some attributes of obj to self.
 """
 if isinstance(obj, ndarray):
 _baseclass = type(obj)
 else:
 _baseclass = ndarray
 # We need to copy the _basedict to avoid backward propagation
 _optinfo = {}
 _optinfo.update(getattr(obj, '_optinfo', {}))
 _optinfo.update(getattr(obj, '_basedict', {}))
 if not isinstance(obj, MaskedArray):
 _optinfo.update(getattr(obj, '__dict__', {}))
 _dict = {'_fill_value': getattr(obj, '_fill_value', None),
 '_hardmask': getattr(obj, '_hardmask', False),
 '_sharedmask': getattr(obj, '_sharedmask', False),
 '_isfield': getattr(obj, '_isfield', False),
 '_baseclass': getattr(obj, '_baseclass', _baseclass),
 '_optinfo': _optinfo,
 '_basedict': _optinfo}
 self.__dict__.update(_dict)
 self.__dict__.update(_optinfo)
def __array_finalize__(self, obj):
 """
 Finalizes the masked array.
 """
 # Get main attributes.
 self._update_from(obj)
# We have to decide how to initialize self.mask, based on
 # obj.mask. This is very difficult. There might be some
 # correspondence between the elements in the array we are being
 # created from (= obj) and us. Or there might not. This method can
 # be called in all kinds of places for all kinds of reasons -- could
 # be empty_like, could be slicing, could be a ufunc, could be a view.
 # The numpy subclassing interface simply doesn't give us any way
 # to know, which means that at best this method will be based on
 # guesswork and heuristics. To make things worse, there isn't even any
 # clear consensus about what the desired behavior is. For instance,
 # most users think that np.empty_like(marr) -- which goes via this
 # method -- should return a masked array with an empty mask (see
 # gh-3404 and linked discussions), but others disagree, and they have
 # existing code which depends on empty_like returning an array that
 # matches the input mask.
 #
 # Historically our algorithm was: if the template object mask had the
 # same *number of elements* as us, then we used *it's mask object
 # itself* as our mask, so that writes to us would also write to the
 # original array. This is horribly broken in multiple ways.
 #
 # Now what we do instead is, if the template object mask has the same
 # number of elements as us, and we do not have the same base pointer
 # as the template object (b/c views like arr[...] should keep the same
 # mask), then we make a copy of the template object mask and use
 # that. This is also horribly broken but somewhat less so. Maybe.
 if isinstance(obj, ndarray):
 # XX: This looks like a bug -- shouldn't it check self.dtype
 # instead?
 if obj.dtype.names is not None:
 _mask = getmaskarray(obj)
 else:
 _mask = getmask(obj)
# If self and obj point to exactly the same data, then probably
 # self is a simple view of obj (e.g., self = obj[...]), so they
 # should share the same mask. (This isn't 100% reliable, e.g. self
 # could be the first row of obj, or have strange strides, but as a
 # heuristic it's not bad.) In all other cases, we make a copy of
 # the mask, so that future modifications to 'self' do not end up
 # side-effecting 'obj' as well.
 if (_mask is not nomask and obj.__array_interface__["data"][0]
 != self.__array_interface__["data"][0]):
 # We should make a copy. But we could get here via astype,
 # in which case the mask might need a new dtype as well
 # (e.g., changing to or from a structured dtype), and the
 # order could have changed. So, change the mask type if
 # needed and use astype instead of copy.
 if self.dtype == obj.dtype:
 _mask_dtype = _mask.dtype
 else:
 _mask_dtype = make_mask_descr(self.dtype)
if self.flags.c_contiguous:
 order = "C"
 elif self.flags.f_contiguous:
 order = "F"
 else:
 order = "K"
_mask = _mask.astype(_mask_dtype, order)
 else:
 # Take a view so shape changes, etc., do not propagate back.
 _mask = _mask.view()
 else:
 _mask = nomask
self._mask = _mask
 # Finalize the mask
 if self._mask is not nomask:
 try:
 self._mask.shape = self.shape
 except ValueError:
 self._mask = nomask
 except (TypeError, AttributeError):
 # When _mask.shape is not writable (because it's a void)
 pass
# Finalize the fill_value
 if self._fill_value is not None:
 self._fill_value = _check_fill_value(self._fill_value, self.dtype)
 elif self.dtype.names is not None:
 # Finalize the default fill_value for structured arrays
 self._fill_value = _check_fill_value(None, self.dtype)
def __array_wrap__(self, obj, context=None, return_scalar=False):
 """
 Special hook for ufuncs.
 Wraps the numpy array and sets the mask according to context.
 """
 if obj is self: # for in-place operations
 result = obj
 else:
 result = obj.view(type(self))
 result._update_from(self)
if context is not None:
 result._mask = result._mask.copy()
 func, args, out_i = context
 # args sometimes contains outputs (gh-10459), which we don't want
 input_args = args[:func.nin]
 m = functools.reduce(mask_or, [getmaskarray(arg) for arg in input_args])
 # Get the domain mask
 domain = ufunc_domain.get(func)
 if domain is not None:
 # Take the domain, and make sure it's a ndarray
 with np.errstate(divide='ignore', invalid='ignore'):
 # The result may be masked for two (unary) domains.
 # That can't really be right as some domains drop
 # the mask and some don't behaving differently here.
 d = domain(*input_args).astype(bool, copy=False)
 d = filled(d, True)
if d.any():
 # Fill the result where the domain is wrong
 try:
 # Binary domain: take the last value
 fill_value = ufunc_fills[func][-1]
 except TypeError:
 # Unary domain: just use this one
 fill_value = ufunc_fills[func]
 except KeyError:
 # Domain not recognized, use fill_value instead
 fill_value = self.fill_value
np.copyto(result, fill_value, where=d)
# Update the mask
 if m is nomask:
 m = d
 else:
 # Don't modify inplace, we risk back-propagation
 m = (m | d)
# Make sure the mask has the proper size
 if result is not self and result.shape == () and m:
 return masked
 else:
 result._mask = m
 result._sharedmask = False
return result
def view(self, dtype=None, type=None, fill_value=None):
 """
 Return a view of the MaskedArray data.
 Parameters
 ----------
 dtype : data-type or ndarray sub-class, optional
 Data-type descriptor of the returned view, e.g., float32 or int16.
 The default, None, results in the view having the same data-type
 as `a`. As with ``ndarray.view``, dtype can also be specified as
 an ndarray sub-class, which then specifies the type of the
 returned object (this is equivalent to setting the ``type``
 parameter).
 type : Python type, optional
 Type of the returned view, either ndarray or a subclass. The
 default None results in type preservation.
 fill_value : scalar, optional
 The value to use for invalid entries (None by default).
 If None, then this argument is inferred from the passed `dtype`, or
 in its absence the original array, as discussed in the notes below.
 See Also
 --------
 numpy.ndarray.view : Equivalent method on ndarray object.
 Notes
 -----
 ``a.view()`` is used two different ways:
 ``a.view(some_dtype)`` or ``a.view(dtype=some_dtype)`` constructs a view
 of the array's memory with a different data-type. This can cause a
 reinterpretation of the bytes of memory.
 ``a.view(ndarray_subclass)`` or ``a.view(type=ndarray_subclass)`` just
 returns an instance of `ndarray_subclass` that looks at the same array
 (same shape, dtype, etc.) This does not cause a reinterpretation of the
 memory.
 If `fill_value` is not specified, but `dtype` is specified (and is not
 an ndarray sub-class), the `fill_value` of the MaskedArray will be
 reset. If neither `fill_value` nor `dtype` are specified (or if
 `dtype` is an ndarray sub-class), then the fill value is preserved.
 Finally, if `fill_value` is specified, but `dtype` is not, the fill
 value is set to the specified value.
 For ``a.view(some_dtype)``, if ``some_dtype`` has a different number of
 bytes per entry than the previous dtype (for example, converting a
 regular array to a structured array), then the behavior of the view
 cannot be predicted just from the superficial appearance of ``a`` (shown
 by ``print(a)``). It also depends on exactly how ``a`` is stored in
 memory. Therefore if ``a`` is C-ordered versus fortran-ordered, versus
 defined as a slice or transpose, etc., the view may give different
 results.
 """
if dtype is None:
 if type is None:
 output = ndarray.view(self)
 else:
 output = ndarray.view(self, type)
 elif type is None:
 try:
 if issubclass(dtype, ndarray):
 output = ndarray.view(self, dtype)
 dtype = None
 else:
 output = ndarray.view(self, dtype)
 except TypeError:
 output = ndarray.view(self, dtype)
 else:
 output = ndarray.view(self, dtype, type)
# also make the mask be a view (so attr changes to the view's
 # mask do no affect original object's mask)
 # (especially important to avoid affecting np.masked singleton)
 if getmask(output) is not nomask:
 output._mask = output._mask.view()
# Make sure to reset the _fill_value if needed
 if getattr(output, '_fill_value', None) is not None:
 if fill_value is None:
 if dtype is None:
 pass # leave _fill_value as is
 else:
 output._fill_value = None
 else:
 output.fill_value = fill_value
 return output
def __getitem__(self, indx):
 """
 x.__getitem__(y) <==> x[y]
 Return the item described by i, as a masked array.
 """
 # We could directly use ndarray.__getitem__ on self.
 # But then we would have to modify __array_finalize__ to prevent the
 # mask of being reshaped if it hasn't been set up properly yet
 # So it's easier to stick to the current version
 dout = self.data[indx]
 _mask = self._mask
def _is_scalar(m):
 return not isinstance(m, np.ndarray)
def _scalar_heuristic(arr, elem):
 """
 Return whether `elem` is a scalar result of indexing `arr`, or None
 if undecidable without promoting nomask to a full mask
 """
 # obviously a scalar
 if not isinstance(elem, np.ndarray):
 return True
# object array scalar indexing can return anything
 elif arr.dtype.type is np.object_:
 if arr.dtype is not elem.dtype:
 # elem is an array, but dtypes do not match, so must be
 # an element
 return True
# well-behaved subclass that only returns 0d arrays when
 # expected - this is not a scalar
 elif type(arr).__getitem__ == ndarray.__getitem__:
 return False
return None
if _mask is not nomask:
 # _mask cannot be a subclass, so it tells us whether we should
 # expect a scalar. It also cannot be of dtype object.
 mout = _mask[indx]
 scalar_expected = _is_scalar(mout)
else:
 # attempt to apply the heuristic to avoid constructing a full mask
 mout = nomask
 scalar_expected = _scalar_heuristic(self.data, dout)
 if scalar_expected is None:
 # heuristics have failed
 # construct a full array, so we can be certain. This is costly.
 # we could also fall back on ndarray.__getitem__(self.data, indx)
 scalar_expected = _is_scalar(getmaskarray(self)[indx])
# Did we extract a single item?
 if scalar_expected:
 # A record
 if isinstance(dout, np.void):
 # We should always re-cast to mvoid, otherwise users can
 # change masks on rows that already have masked values, but not
 # on rows that have no masked values, which is inconsistent.
 return mvoid(dout, mask=mout, hardmask=self._hardmask)
# special case introduced in gh-5962
 elif (self.dtype.type is np.object_ and
 isinstance(dout, np.ndarray) and
 dout is not masked):
 # If masked, turn into a MaskedArray, with everything masked.
 if mout:
 return MaskedArray(dout, mask=True)
 else:
 return dout
# Just a scalar
 elif mout:
 return masked
 else:
 return dout
 else:
 # Force dout to MA
 dout = dout.view(type(self))
 # Inherit attributes from self
 dout._update_from(self)
 # Check the fill_value
 if is_string_or_list_of_strings(indx):
 if self._fill_value is not None:
 dout._fill_value = self._fill_value[indx]
# Something like gh-15895 has happened if this check fails.
 # _fill_value should always be an ndarray.
 if not isinstance(dout._fill_value, np.ndarray):
 raise RuntimeError('Internal NumPy error.')
 # If we're indexing a multidimensional field in a
 # structured array (such as dtype("(2,)i2,(2,)i1")),
 # dimensionality goes up (M[field].ndim == M.ndim +
 # M.dtype[field].ndim). That's fine for
 # M[field] but problematic for M[field].fill_value
 # which should have shape () to avoid breaking several
 # methods. There is no great way out, so set to
 # first element. See issue #6723.
 if dout._fill_value.ndim > 0:
 if not (dout._fill_value ==
 dout._fill_value.flat[0]).all():
 warnings.warn(
 "Upon accessing multidimensional field "
 f"{indx!s}, need to keep dimensionality "
 "of fill_value at 0. Discarding "
 "heterogeneous fill_value and setting "
 f"all to {dout._fill_value[0]!s}.",
 stacklevel=2)
 # Need to use `.flat[0:1].squeeze(...)` instead of just
 # `.flat[0]` to ensure the result is a 0d array and not
 # a scalar.
 dout._fill_value = dout._fill_value.flat[0:1].squeeze(axis=0)
 dout._isfield = True
 # Update the mask if needed
 if mout is not nomask:
 # set shape to match that of data; this is needed for matrices
 dout._mask = reshape(mout, dout.shape)
 dout._sharedmask = True
 # Note: Don't try to check for m.any(), that'll take too long
 return dout
# setitem may put NaNs into integer arrays or occasionally overflow a
 # float. But this may happen in masked values, so avoid otherwise
 # correct warnings (as is typical also in masked calculations).
 @np.errstate(over='ignore', invalid='ignore')
 def __setitem__(self, indx, value):
 """
 x.__setitem__(i, y) <==> x[i]=y
 Set item described by index. If value is masked, masks those
 locations.
 """
 if self is masked:
 raise MaskError('Cannot alter the masked element.')
 _data = self._data
 _mask = self._mask
 if isinstance(indx, str):
 _data[indx] = value
 if _mask is nomask:
 self._mask = _mask = make_mask_none(self.shape, self.dtype)
 _mask[indx] = getmask(value)
 return
_dtype = _data.dtype
if value is masked:
 # The mask wasn't set: create a full version.
 if _mask is nomask:
 _mask = self._mask = make_mask_none(self.shape, _dtype)
 # Now, set the mask to its value.
 if _dtype.names is not None:
 _mask[indx] = tuple([True] * len(_dtype.names))
 else:
 _mask[indx] = True
 return
# Get the _data part of the new value
 dval = getattr(value, '_data', value)
 # Get the _mask part of the new value
 mval = getmask(value)
 if _dtype.names is not None and mval is nomask:
 mval = tuple([False] * len(_dtype.names))
 if _mask is nomask:
 # Set the data, then the mask
 _data[indx] = dval
 if mval is not nomask:
 _mask = self._mask = make_mask_none(self.shape, _dtype)
 _mask[indx] = mval
 elif not self._hardmask:
 # Set the data, then the mask
 if (isinstance(indx, masked_array) and
 not isinstance(value, masked_array)):
 _data[indx.data] = dval
 else:
 _data[indx] = dval
 _mask[indx] = mval
 elif hasattr(indx, 'dtype') and (indx.dtype == MaskType):
 indx = indx * umath.logical_not(_mask)
 _data[indx] = dval
 else:
 if _dtype.names is not None:
 err_msg = "Flexible 'hard' masks are not yet supported."
 raise NotImplementedError(err_msg)
 mindx = mask_or(_mask[indx], mval, copy=True)
 dindx = self._data[indx]
 if dindx.size > 1:
 np.copyto(dindx, dval, where=~mindx)
 elif mindx is nomask:
 dindx = dval
 _data[indx] = dindx
 _mask[indx] = mindx
 return
# Define so that we can overwrite the setter.
 @property
 def dtype(self):
 return super().dtype
@dtype.setter
 def dtype(self, dtype):
 super(MaskedArray, type(self)).dtype.__set__(self, dtype)
 if self._mask is not nomask:
 self._mask = self._mask.view(make_mask_descr(dtype), ndarray)
 # Try to reset the shape of the mask (if we don't have a void).
 # This raises a ValueError if the dtype change won't work.
 try:
 self._mask.shape = self.shape
 except (AttributeError, TypeError):
 pass
@property
 def shape(self):
 return super().shape
@shape.setter
 def shape(self, shape):
 super(MaskedArray, type(self)).shape.__set__(self, shape)
 # Cannot use self._mask, since it may not (yet) exist when a
 # masked matrix sets the shape.
 if getmask(self) is not nomask:
 self._mask.shape = self.shape
def __setmask__(self, mask, copy=False):
 """
 Set the mask.
 """
 idtype = self.dtype
 current_mask = self._mask
 if mask is masked:
 mask = True
if current_mask is nomask:
 # Make sure the mask is set
 # Just don't do anything if there's nothing to do.
 if mask is nomask:
 return
 current_mask = self._mask = make_mask_none(self.shape, idtype)
if idtype.names is None:
 # No named fields.
 # Hardmask: don't unmask the data
 if self._hardmask:
 current_mask |= mask
 # Softmask: set everything to False
 # If it's obviously a compatible scalar, use a quick update
 # method.
 elif isinstance(mask, (int, float, np.bool, np.number)):
 current_mask[...] = mask
 # Otherwise fall back to the slower, general purpose way.
 else:
 current_mask.flat = mask
 else:
 # Named fields w/
 mdtype = current_mask.dtype
 mask = np.asarray(mask)
 # Mask is a singleton
 if not mask.ndim:
 # It's a boolean : make a record
 if mask.dtype.kind == 'b':
 mask = np.array(tuple([mask.item()] * len(mdtype)),
 dtype=mdtype)
 # It's a record: make sure the dtype is correct
 else:
 mask = mask.astype(mdtype)
 # Mask is a sequence
 else:
 # Make sure the new mask is a ndarray with the proper dtype
 try:
 copy = None if not copy else True
 mask = np.array(mask, copy=copy, dtype=mdtype)
 # Or assume it's a sequence of bool/int
 except TypeError:
 mask = np.array([tuple([m] * len(mdtype)) for m in mask],
 dtype=mdtype)
 # Hardmask: don't unmask the data
 if self._hardmask:
 for n in idtype.names:
 current_mask[n] |= mask[n]
 # Softmask: set everything to False
 # If it's obviously a compatible scalar, use a quick update
 # method.
 elif isinstance(mask, (int, float, np.bool, np.number)):
 current_mask[...] = mask
 # Otherwise fall back to the slower, general purpose way.
 else:
 current_mask.flat = mask
 # Reshape if needed
 if current_mask.shape:
 current_mask.shape = self.shape
 return
_set_mask = __setmask__
@property
 def mask(self):
 """ Current mask. """
# We could try to force a reshape, but that wouldn't work in some
 # cases.
 # Return a view so that the dtype and shape cannot be changed in place
 # This still preserves nomask by identity
 return self._mask.view()
@mask.setter
 def mask(self, value):
 self.__setmask__(value)
@property
 def recordmask(self):
 """
 Get or set the mask of the array if it has no named fields. For
 structured arrays, returns a ndarray of booleans where entries are
 ``True`` if **all** the fields are masked, ``False`` otherwise:
 >>> x = np.ma.array([(1, 1), (2, 2), (3, 3), (4, 4), (5, 5)],
 ... mask=[(0, 0), (1, 0), (1, 1), (0, 1), (0, 0)],
 ... dtype=[('a', int), ('b', int)])
 >>> x.recordmask
 array([False, False, True, False, False])
 """
_mask = self._mask.view(ndarray)
 if _mask.dtype.names is None:
 return _mask
 return np.all(flatten_structured_array(_mask), axis=-1)
@recordmask.setter
 def recordmask(self, mask):
 raise NotImplementedError("Coming soon: setting the mask per records!")
def harden_mask(self):
 """
 Force the mask to hard, preventing unmasking by assignment.
 Whether the mask of a masked array is hard or soft is determined by
 its `~ma.MaskedArray.hardmask` property. `harden_mask` sets
 `~ma.MaskedArray.hardmask` to ``True`` (and returns the modified
 self).
 See Also
 --------
 ma.MaskedArray.hardmask
 ma.MaskedArray.soften_mask
 """
 self._hardmask = True
 return self
def soften_mask(self):
 """
 Force the mask to soft (default), allowing unmasking by assignment.
 Whether the mask of a masked array is hard or soft is determined by
 its `~ma.MaskedArray.hardmask` property. `soften_mask` sets
 `~ma.MaskedArray.hardmask` to ``False`` (and returns the modified
 self).
 See Also
 --------
 ma.MaskedArray.hardmask
 ma.MaskedArray.harden_mask
 """
 self._hardmask = False
 return self
@property
 def hardmask(self):
 """
 Specifies whether values can be unmasked through assignments.
 By default, assigning definite values to masked array entries will
 unmask them. When `hardmask` is ``True``, the mask will not change
 through assignments.
 See Also
 --------
 ma.MaskedArray.harden_mask
 ma.MaskedArray.soften_mask
 Examples
 --------
 >>> import numpy as np
 >>> x = np.arange(10)
 >>> m = np.ma.masked_array(x, x>5)
 >>> assert not m.hardmask
 Since `m` has a soft mask, assigning an element value unmasks that
 element:
 >>> m[8] = 42
 >>> m
 masked_array(data=[0, 1, 2, 3, 4, 5, --, --, 42, --],
 mask=[False, False, False, False, False, False,
 True, True, False, True],
 fill_value=999999)
 After hardening, the mask is not affected by assignments:
 >>> hardened = np.ma.harden_mask(m)
 >>> assert m.hardmask and hardened is m
 >>> m[:] = 23
 >>> m
 masked_array(data=[23, 23, 23, 23, 23, 23, --, --, 23, --],
 mask=[False, False, False, False, False, False,
 True, True, False, True],
 fill_value=999999)
 """
 return self._hardmask
def unshare_mask(self):
 """
 Copy the mask and set the `sharedmask` flag to ``False``.
 Whether the mask is shared between masked arrays can be seen from
 the `sharedmask` property. `unshare_mask` ensures the mask is not
 shared. A copy of the mask is only made if it was shared.
 See Also
 --------
 sharedmask
 """
 if self._sharedmask:
 self._mask = self._mask.copy()
 self._sharedmask = False
 return self
@property
 def sharedmask(self):
 """ Share status of the mask (read-only). """
 return self._sharedmask
def shrink_mask(self):
 """
 Reduce a mask to nomask when possible.
 Parameters
 ----------
 None
 Returns
 -------
 result : MaskedArray
 A :class:`~ma.MaskedArray` object.
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array([[1,2 ], [3, 4]], mask=[0]*4)
 >>> x.mask
 array([[False, False],
 [False, False]])
 >>> x.shrink_mask()
 masked_array(
 data=[[1, 2],
 [3, 4]],
 mask=False,
 fill_value=999999)
 >>> x.mask
 False
 """
 self._mask = _shrink_mask(self._mask)
 return self
@property
 def baseclass(self):
 """ Class of the underlying data (read-only). """
 return self._baseclass
def _get_data(self):
 """
 Returns the underlying data, as a view of the masked array.
 If the underlying data is a subclass of :class:`numpy.ndarray`, it is
 returned as such.
 >>> x = np.ma.array(np.matrix([[1, 2], [3, 4]]), mask=[[0, 1], [1, 0]])
 >>> x.data
 matrix([[1, 2],
 [3, 4]])
 The type of the data can be accessed through the :attr:`baseclass`
 attribute.
 """
 return ndarray.view(self, self._baseclass)
_data = property(fget=_get_data)
 data = property(fget=_get_data)
@property
 def flat(self):
 """ Return a flat iterator, or set a flattened version of self to value. """
 return MaskedIterator(self)
@flat.setter
 def flat(self, value):
 y = self.ravel()
 y[:] = value
@property
 def fill_value(self):
 """
 The filling value of the masked array is a scalar. When setting, None
 will set to a default based on the data type.
 Examples
 --------
 >>> import numpy as np
 >>> for dt in [np.int32, np.int64, np.float64, np.complex128]:
 ... np.ma.array([0, 1], dtype=dt).get_fill_value()
 ...
 np.int64(999999)
 np.int64(999999)
 np.float64(1e+20)
 np.complex128(1e+20+0j)
 >>> x = np.ma.array([0, 1.], fill_value=-np.inf)
 >>> x.fill_value
 np.float64(-inf)
 >>> x.fill_value = np.pi
 >>> x.fill_value
 np.float64(3.1415926535897931)
 Reset to default:
 >>> x.fill_value = None
 >>> x.fill_value
 np.float64(1e+20)
 """
 if self._fill_value is None:
 self._fill_value = _check_fill_value(None, self.dtype)
# Temporary workaround to account for the fact that str and bytes
 # scalars cannot be indexed with (), whereas all other numpy
 # scalars can. See issues #7259 and #7267.
 # The if-block can be removed after #7267 has been fixed.
 if isinstance(self._fill_value, ndarray):
 return self._fill_value[()]
 return self._fill_value
@fill_value.setter
 def fill_value(self, value=None):
 target = _check_fill_value(value, self.dtype)
 if not target.ndim == 0:
 # 2019-11-12, 1.18.0
 warnings.warn(
 "Non-scalar arrays for the fill value are deprecated. Use "
 "arrays with scalar values instead. The filled function "
 "still supports any array as `fill_value`.",
 DeprecationWarning, stacklevel=2)
_fill_value = self._fill_value
 if _fill_value is None:
 # Create the attribute if it was undefined
 self._fill_value = target
 else:
 # Don't overwrite the attribute, just fill it (for propagation)
 _fill_value[()] = target
# kept for compatibility
 get_fill_value = fill_value.fget
 set_fill_value = fill_value.fset
def filled(self, fill_value=None):
 """
 Return a copy of self, with masked values filled with a given value.
 **However**, if there are no masked values to fill, self will be
 returned instead as an ndarray.
 Parameters
 ----------
 fill_value : array_like, optional
 The value to use for invalid entries. Can be scalar or non-scalar.
 If non-scalar, the resulting ndarray must be broadcastable over
 input array. Default is None, in which case, the `fill_value`
 attribute of the array is used instead.
 Returns
 -------
 filled_array : ndarray
 A copy of ``self`` with invalid entries replaced by *fill_value*
 (be it the function argument or the attribute of ``self``), or
 ``self`` itself as an ndarray if there are no invalid entries to
 be replaced.
 Notes
 -----
 The result is **not** a MaskedArray!
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array([1,2,3,4,5], mask=[0,0,1,0,1], fill_value=-999)
 >>> x.filled()
 array([ 1, 2, -999, 4, -999])
 >>> x.filled(fill_value=1000)
 array([ 1, 2, 1000, 4, 1000])
 >>> type(x.filled())
 <class 'numpy.ndarray'>
 Subclassing is preserved. This means that if, e.g., the data part of
 the masked array is a recarray, `filled` returns a recarray:
 >>> x = np.array([(-1, 2), (-3, 4)], dtype='i8,i8').view(np.recarray)
 >>> m = np.ma.array(x, mask=[(True, False), (False, True)])
 >>> m.filled()
 rec.array([(999999, 2), ( -3, 999999)],
 dtype=[('f0', '<i8'), ('f1', '<i8')])
 """
 m = self._mask
 if m is nomask:
 return self._data
if fill_value is None:
 fill_value = self.fill_value
 else:
 fill_value = _check_fill_value(fill_value, self.dtype)
if self is masked_singleton:
 return np.asanyarray(fill_value)
if m.dtype.names is not None:
 result = self._data.copy('K')
 _recursive_filled(result, self._mask, fill_value)
 elif not m.any():
 return self._data
 else:
 result = self._data.copy('K')
 try:
 np.copyto(result, fill_value, where=m)
 except (TypeError, AttributeError):
 fill_value = narray(fill_value, dtype=object)
 d = result.astype(object)
 result = np.choose(m, (d, fill_value))
 except IndexError:
 # ok, if scalar
 if self._data.shape:
 raise
 elif m:
 result = np.array(fill_value, dtype=self.dtype)
 else:
 result = self._data
 return result
def compressed(self):
 """
 Return all the non-masked data as a 1-D array.
 Returns
 -------
 data : ndarray
 A new `ndarray` holding the non-masked data is returned.
 Notes
 -----
 The result is **not** a MaskedArray!
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array(np.arange(5), mask=[0]*2 + [1]*3)
 >>> x.compressed()
 array([0, 1])
 >>> type(x.compressed())
 <class 'numpy.ndarray'>
 N-D arrays are compressed to 1-D.
 >>> arr = [[1, 2], [3, 4]]
 >>> mask = [[1, 0], [0, 1]]
 >>> x = np.ma.array(arr, mask=mask)
 >>> x.compressed()
 array([2, 3])
 """
 data = ndarray.ravel(self._data)
 if self._mask is not nomask:
 data = data.compress(np.logical_not(ndarray.ravel(self._mask)))
 return data
def compress(self, condition, axis=None, out=None):
 """
 Return `a` where condition is ``True``.
 If condition is a `~ma.MaskedArray`, missing values are considered
 as ``False``.
 Parameters
 ----------
 condition : var
 Boolean 1-d array selecting which entries to return. If len(condition)
 is less than the size of a along the axis, then output is truncated
 to length of condition array.
 axis : {None, int}, optional
 Axis along which the operation must be performed.
 out : {None, ndarray}, optional
 Alternative output array in which to place the result. It must have
 the same shape as the expected output but the type will be cast if
 necessary.
 Returns
 -------
 result : MaskedArray
 A :class:`~ma.MaskedArray` object.
 Notes
 -----
 Please note the difference with :meth:`compressed` !
 The output of :meth:`compress` has a mask, the output of
 :meth:`compressed` does not.
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array([[1,2,3],[4,5,6],[7,8,9]], mask=[0] + [1,0]*4)
 >>> x
 masked_array(
 data=[[1, --, 3],
 [--, 5, --],
 [7, --, 9]],
 mask=[[False, True, False],
 [ True, False, True],
 [False, True, False]],
 fill_value=999999)
 >>> x.compress([1, 0, 1])
 masked_array(data=[1, 3],
 mask=[False, False],
 fill_value=999999)
 >>> x.compress([1, 0, 1], axis=1)
 masked_array(
 data=[[1, 3],
 [--, --],
 [7, 9]],
 mask=[[False, False],
 [ True, True],
 [False, False]],
 fill_value=999999)
 """
 # Get the basic components
 (_data, _mask) = (self._data, self._mask)
# Force the condition to a regular ndarray and forget the missing
 # values.
 condition = np.asarray(condition)
_new = _data.compress(condition, axis=axis, out=out).view(type(self))
 _new._update_from(self)
 if _mask is not nomask:
 _new._mask = _mask.compress(condition, axis=axis)
 return _new
def _insert_masked_print(self):
 """
 Replace masked values with masked_print_option, casting all innermost
 dtypes to object.
 """
 if masked_print_option.enabled():
 mask = self._mask
 if mask is nomask:
 res = self._data
 else:
 # convert to object array to make filled work
 data = self._data
 # For big arrays, to avoid a costly conversion to the
 # object dtype, extract the corners before the conversion.
 print_width = (self._print_width if self.ndim > 1
 else self._print_width_1d)
 for axis in range(self.ndim):
 if data.shape[axis] > print_width:
 ind = print_width // 2
 arr = np.split(data, (ind, -ind), axis=axis)
 data = np.concatenate((arr[0], arr[2]), axis=axis)
 arr = np.split(mask, (ind, -ind), axis=axis)
 mask = np.concatenate((arr[0], arr[2]), axis=axis)
rdtype = _replace_dtype_fields(self.dtype, "O")
 res = data.astype(rdtype)
 _recursive_printoption(res, mask, masked_print_option)
 else:
 res = self.filled(self.fill_value)
 return res
def __str__(self):
 return str(self._insert_masked_print())
def __repr__(self):
 """
 Literal string representation.
 """
 if self._baseclass is np.ndarray:
 name = 'array'
 else:
 name = self._baseclass.__name__
# 2016-11-19: Demoted to legacy format
 if np._core.arrayprint._get_legacy_print_mode() <= 113:
 is_long = self.ndim > 1
 parameters = {
 'name': name,
 'nlen': " " * len(name),
 'data': str(self),
 'mask': str(self._mask),
 'fill': str(self.fill_value),
 'dtype': str(self.dtype)
 }
 is_structured = bool(self.dtype.names)
 key = '{}_{}'.format(
 'long' if is_long else 'short',
 'flx' if is_structured else 'std'
 )
 return _legacy_print_templates[key] % parameters
prefix = f"masked_{name}("
dtype_needed = (
 not np._core.arrayprint.dtype_is_implied(self.dtype) or
 np.all(self.mask) or
 self.size == 0
 )
# determine which keyword args need to be shown
 keys = ['data', 'mask', 'fill_value']
 if dtype_needed:
 keys.append('dtype')
# array has only one row (non-column)
 is_one_row = builtins.all(dim == 1 for dim in self.shape[:-1])
# choose what to indent each keyword with
 min_indent = 2
 if is_one_row:
 # first key on the same line as the type, remaining keys
 # aligned by equals
 indents = {}
 indents[keys[0]] = prefix
 for k in keys[1:]:
 n = builtins.max(min_indent, len(prefix + keys[0]) - len(k))
 indents[k] = ' ' * n
 prefix = '' # absorbed into the first indent
 else:
 # each key on its own line, indented by two spaces
 indents = dict.fromkeys(keys, ' ' * min_indent)
 prefix = prefix + '\n' # first key on the next line
# format the field values
 reprs = {}
 reprs['data'] = np.array2string(
 self._insert_masked_print(),
 separator=", ",
 prefix=indents['data'] + 'data=',
 suffix=',')
 reprs['mask'] = np.array2string(
 self._mask,
 separator=", ",
 prefix=indents['mask'] + 'mask=',
 suffix=',')
if self._fill_value is None:
 self.fill_value # initialize fill_value # noqa: B018
if (self._fill_value.dtype.kind in ("S", "U")
 and self.dtype.kind == self._fill_value.dtype.kind):
 # Allow strings: "N/A" has length 3 so would mismatch.
 fill_repr = repr(self.fill_value.item())
 elif self._fill_value.dtype == self.dtype and not self.dtype == object:
 # Guess that it is OK to use the string as item repr. To really
 # fix this, it needs new logic (shared with structured scalars)
 fill_repr = str(self.fill_value)
 else:
 fill_repr = repr(self.fill_value)
reprs['fill_value'] = fill_repr
 if dtype_needed:
 reprs['dtype'] = np._core.arrayprint.dtype_short_repr(self.dtype)
# join keys with values and indentations
 result = ',\n'.join(
 f'{indents[k]}{k}={reprs[k]}'
 for k in keys
 )
 return prefix + result + ')'
def _delegate_binop(self, other):
 # This emulates the logic in
 # private/binop_override.h:forward_binop_should_defer
 if isinstance(other, type(self)):
 return False
 array_ufunc = getattr(other, "__array_ufunc__", False)
 if array_ufunc is False:
 other_priority = getattr(other, "__array_priority__", -1000000)
 return self.__array_priority__ < other_priority
 else:
 # If array_ufunc is not None, it will be called inside the ufunc;
 # None explicitly tells us to not call the ufunc, i.e., defer.
 return array_ufunc is None
def _comparison(self, other, compare):
 """Compare self with other using operator.eq or operator.ne.
 When either of the elements is masked, the result is masked as well,
 but the underlying boolean data are still set, with self and other
 considered equal if both are masked, and unequal otherwise.
 For structured arrays, all fields are combined, with masked values
 ignored. The result is masked if all fields were masked, with self
 and other considered equal only if both were fully masked.
 """
 omask = getmask(other)
 smask = self.mask
 mask = mask_or(smask, omask, copy=True)
odata = getdata(other)
 if mask.dtype.names is not None:
 # only == and != are reasonably defined for structured dtypes,
 # so give up early for all other comparisons:
 if compare not in (operator.eq, operator.ne):
 return NotImplemented
 # For possibly masked structured arrays we need to be careful,
 # since the standard structured array comparison will use all
 # fields, masked or not. To avoid masked fields influencing the
 # outcome, we set all masked fields in self to other, so they'll
 # count as equal. To prepare, we ensure we have the right shape.
 broadcast_shape = np.broadcast(self, odata).shape
 sbroadcast = np.broadcast_to(self, broadcast_shape, subok=True)
 sbroadcast._mask = mask
 sdata = sbroadcast.filled(odata)
 # Now take care of the mask; the merged mask should have an item
 # masked if all fields were masked (in one and/or other).
 mask = (mask == np.ones((), mask.dtype))
 # Ensure we can compare masks below if other was not masked.
 if omask is np.False_:
 omask = np.zeros((), smask.dtype)
else:
 # For regular arrays, just use the data as they come.
 sdata = self.data
check = compare(sdata, odata)
if isinstance(check, (np.bool, bool)):
 return masked if mask else check
if mask is not nomask:
 if compare in (operator.eq, operator.ne):
 # Adjust elements that were masked, which should be treated
 # as equal if masked in both, unequal if masked in one.
 # Note that this works automatically for structured arrays too.
 # Ignore this for operations other than `==` and `!=`
 check = np.where(mask, compare(smask, omask), check)
if mask.shape != check.shape:
 # Guarantee consistency of the shape, making a copy since the
 # the mask may need to get written to later.
 mask = np.broadcast_to(mask, check.shape).copy()
check = check.view(type(self))
 check._update_from(self)
 check._mask = mask
# Cast fill value to np.bool if needed. If it cannot be cast, the
 # default boolean fill value is used.
 if check._fill_value is not None:
 try:
 fill = _check_fill_value(check._fill_value, np.bool)
 except (TypeError, ValueError):
 fill = _check_fill_value(None, np.bool)
 check._fill_value = fill
return check
def __eq__(self, other):
 """Check whether other equals self elementwise.
 When either of the elements is masked, the result is masked as well,
 but the underlying boolean data are still set, with self and other
 considered equal if both are masked, and unequal otherwise.
 For structured arrays, all fields are combined, with masked values
 ignored. The result is masked if all fields were masked, with self
 and other considered equal only if both were fully masked.
 """
 return self._comparison(other, operator.eq)
def __ne__(self, other):
 """Check whether other does not equal self elementwise.
 When either of the elements is masked, the result is masked as well,
 but the underlying boolean data are still set, with self and other
 considered equal if both are masked, and unequal otherwise.
 For structured arrays, all fields are combined, with masked values
 ignored. The result is masked if all fields were masked, with self
 and other considered equal only if both were fully masked.
 """
 return self._comparison(other, operator.ne)
# All other comparisons:
 def __le__(self, other):
 return self._comparison(other, operator.le)
def __lt__(self, other):
 return self._comparison(other, operator.lt)
def __ge__(self, other):
 return self._comparison(other, operator.ge)
def __gt__(self, other):
 return self._comparison(other, operator.gt)
def __add__(self, other):
 """
 Add self to other, and return a new masked array.
 """
 if self._delegate_binop(other):
 return NotImplemented
 return add(self, other)
def __radd__(self, other):
 """
 Add other to self, and return a new masked array.
 """
 # In analogy with __rsub__ and __rdiv__, use original order:
 # we get here from `other + self`.
 return add(other, self)
def __sub__(self, other):
 """
 Subtract other from self, and return a new masked array.
 """
 if self._delegate_binop(other):
 return NotImplemented
 return subtract(self, other)
def __rsub__(self, other):
 """
 Subtract self from other, and return a new masked array.
 """
 return subtract(other, self)
def __mul__(self, other):
 "Multiply self by other, and return a new masked array."
 if self._delegate_binop(other):
 return NotImplemented
 return multiply(self, other)
def __rmul__(self, other):
 """
 Multiply other by self, and return a new masked array.
 """
 # In analogy with __rsub__ and __rdiv__, use original order:
 # we get here from `other * self`.
 return multiply(other, self)
def __truediv__(self, other):
 """
 Divide other into self, and return a new masked array.
 """
 if self._delegate_binop(other):
 return NotImplemented
 return true_divide(self, other)
def __rtruediv__(self, other):
 """
 Divide self into other, and return a new masked array.
 """
 return true_divide(other, self)
def __floordiv__(self, other):
 """
 Divide other into self, and return a new masked array.
 """
 if self._delegate_binop(other):
 return NotImplemented
 return floor_divide(self, other)
def __rfloordiv__(self, other):
 """
 Divide self into other, and return a new masked array.
 """
 return floor_divide(other, self)
def __pow__(self, other):
 """
 Raise self to the power other, masking the potential NaNs/Infs
 """
 if self._delegate_binop(other):
 return NotImplemented
 return power(self, other)
def __rpow__(self, other):
 """
 Raise other to the power self, masking the potential NaNs/Infs
 """
 return power(other, self)
def __iadd__(self, other):
 """
 Add other to self in-place.
 """
 m = getmask(other)
 if self._mask is nomask:
 if m is not nomask and m.any():
 self._mask = make_mask_none(self.shape, self.dtype)
 self._mask += m
 elif m is not nomask:
 self._mask += m
 other_data = getdata(other)
 other_data = np.where(self._mask, other_data.dtype.type(0), other_data)
 self._data.__iadd__(other_data)
 return self
def __isub__(self, other):
 """
 Subtract other from self in-place.
 """
 m = getmask(other)
 if self._mask is nomask:
 if m is not nomask and m.any():
 self._mask = make_mask_none(self.shape, self.dtype)
 self._mask += m
 elif m is not nomask:
 self._mask += m
 other_data = getdata(other)
 other_data = np.where(self._mask, other_data.dtype.type(0), other_data)
 self._data.__isub__(other_data)
 return self
def __imul__(self, other):
 """
 Multiply self by other in-place.
 """
 m = getmask(other)
 if self._mask is nomask:
 if m is not nomask and m.any():
 self._mask = make_mask_none(self.shape, self.dtype)
 self._mask += m
 elif m is not nomask:
 self._mask += m
 other_data = getdata(other)
 other_data = np.where(self._mask, other_data.dtype.type(1), other_data)
 self._data.__imul__(other_data)
 return self
def __ifloordiv__(self, other):
 """
 Floor divide self by other in-place.
 """
 other_data = getdata(other)
 dom_mask = _DomainSafeDivide().__call__(self._data, other_data)
 other_mask = getmask(other)
 new_mask = mask_or(other_mask, dom_mask)
 # The following 3 lines control the domain filling
 if dom_mask.any():
 (_, fval) = ufunc_fills[np.floor_divide]
 other_data = np.where(
 dom_mask, other_data.dtype.type(fval), other_data)
 self._mask |= new_mask
 other_data = np.where(self._mask, other_data.dtype.type(1), other_data)
 self._data.__ifloordiv__(other_data)
 return self
def __itruediv__(self, other):
 """
 True divide self by other in-place.
 """
 other_data = getdata(other)
 dom_mask = _DomainSafeDivide().__call__(self._data, other_data)
 other_mask = getmask(other)
 new_mask = mask_or(other_mask, dom_mask)
 # The following 3 lines control the domain filling
 if dom_mask.any():
 (_, fval) = ufunc_fills[np.true_divide]
 other_data = np.where(
 dom_mask, other_data.dtype.type(fval), other_data)
 self._mask |= new_mask
 other_data = np.where(self._mask, other_data.dtype.type(1), other_data)
 self._data.__itruediv__(other_data)
 return self
def __ipow__(self, other):
 """
 Raise self to the power other, in place.
 """
 other_data = getdata(other)
 other_data = np.where(self._mask, other_data.dtype.type(1), other_data)
 other_mask = getmask(other)
 with np.errstate(divide='ignore', invalid='ignore'):
 self._data.__ipow__(other_data)
 invalid = np.logical_not(np.isfinite(self._data))
 if invalid.any():
 if self._mask is not nomask:
 self._mask |= invalid
 else:
 self._mask = invalid
 np.copyto(self._data, self.fill_value, where=invalid)
 new_mask = mask_or(other_mask, invalid)
 self._mask = mask_or(self._mask, new_mask)
 return self
def __float__(self):
 """
 Convert to float.
 """
 if self.size > 1:
 raise TypeError("Only length-1 arrays can be converted "
 "to Python scalars")
 elif self._mask:
 warnings.warn("Warning: converting a masked element to nan.", stacklevel=2)
 return np.nan
 return float(self.item())
def __int__(self):
 """
 Convert to int.
 """
 if self.size > 1:
 raise TypeError("Only length-1 arrays can be converted "
 "to Python scalars")
 elif self._mask:
 raise MaskError('Cannot convert masked element to a Python int.')
 return int(self.item())
@property
 def imag(self):
 """
 The imaginary part of the masked array.
 This property is a view on the imaginary part of this `MaskedArray`.
 See Also
 --------
 real
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array([1+1.j, -2j, 3.45+1.6j], mask=[False, True, False])
 >>> x.imag
 masked_array(data=[1.0, --, 1.6],
 mask=[False, True, False],
 fill_value=1e+20)
 """
 result = self._data.imag.view(type(self))
 result.__setmask__(self._mask)
 return result
# kept for compatibility
 get_imag = imag.fget
@property
 def real(self):
 """
 The real part of the masked array.
 This property is a view on the real part of this `MaskedArray`.
 See Also
 --------
 imag
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array([1+1.j, -2j, 3.45+1.6j], mask=[False, True, False])
 >>> x.real
 masked_array(data=[1.0, --, 3.45],
 mask=[False, True, False],
 fill_value=1e+20)
 """
 result = self._data.real.view(type(self))
 result.__setmask__(self._mask)
 return result
# kept for compatibility
 get_real = real.fget
def count(self, axis=None, keepdims=np._NoValue):
 """
 Count the non-masked elements of the array along the given axis.
 Parameters
 ----------
 axis : None or int or tuple of ints, optional
 Axis or axes along which the count is performed.
 The default, None, performs the count over all
 the dimensions of the input array. `axis` may be negative, in
 which case it counts from the last to the first axis.
 If this is a tuple of ints, the count is performed on multiple
 axes, instead of a single axis or all the axes as before.
 keepdims : bool, optional
 If this is set to True, the axes which are reduced are left
 in the result as dimensions with size one. With this option,
 the result will broadcast correctly against the array.
 Returns
 -------
 result : ndarray or scalar
 An array with the same shape as the input array, with the specified
 axis removed. If the array is a 0-d array, or if `axis` is None, a
 scalar is returned.
 See Also
 --------
 ma.count_masked : Count masked elements in array or along a given axis.
 Examples
 --------
 >>> import numpy.ma as ma
 >>> a = ma.arange(6).reshape((2, 3))
 >>> a[1, :] = ma.masked
 >>> a
 masked_array(
 data=[[0, 1, 2],
 [--, --, --]],
 mask=[[False, False, False],
 [ True, True, True]],
 fill_value=999999)
 >>> a.count()
 3
 When the `axis` keyword is specified an array of appropriate size is
 returned.
 >>> a.count(axis=0)
 array([1, 1, 1])
 >>> a.count(axis=1)
 array([3, 0])
 """
 kwargs = {} if keepdims is np._NoValue else {'keepdims': keepdims}
m = self._mask
 # special case for matrices (we assume no other subclasses modify
 # their dimensions)
 if isinstance(self.data, np.matrix):
 if m is nomask:
 m = np.zeros(self.shape, dtype=np.bool)
 m = m.view(type(self.data))
if m is nomask:
 # compare to _count_reduce_items in _methods.py
if self.shape == ():
 if axis not in (None, 0):
 raise np.exceptions.AxisError(axis=axis, ndim=self.ndim)
 return 1
 elif axis is None:
 if kwargs.get('keepdims'):
 return np.array(self.size, dtype=np.intp, ndmin=self.ndim)
 return self.size
axes = normalize_axis_tuple(axis, self.ndim)
 items = 1
 for ax in axes:
 items *= self.shape[ax]
if kwargs.get('keepdims'):
 out_dims = list(self.shape)
 for a in axes:
 out_dims[a] = 1
 else:
 out_dims = [d for n, d in enumerate(self.shape)
 if n not in axes]
 # make sure to return a 0-d array if axis is supplied
 return np.full(out_dims, items, dtype=np.intp)
# take care of the masked singleton
 if self is masked:
 return 0
return (~m).sum(axis=axis, dtype=np.intp, **kwargs)
def ravel(self, order='C'):
 """
 Returns a 1D version of self, as a view.
 Parameters
 ----------
 order : {'C', 'F', 'A', 'K'}, optional
 The elements of `a` are read using this index order. 'C' means to
 index the elements in C-like order, with the last axis index
 changing fastest, back to the first axis index changing slowest.
 'F' means to index the elements in Fortran-like index order, with
 the first index changing fastest, and the last index changing
 slowest. Note that the 'C' and 'F' options take no account of the
 memory layout of the underlying array, and only refer to the order
 of axis indexing. 'A' means to read the elements in Fortran-like
 index order if `m` is Fortran *contiguous* in memory, C-like order
 otherwise. 'K' means to read the elements in the order they occur
 in memory, except for reversing the data when strides are negative.
 By default, 'C' index order is used.
 (Masked arrays currently use 'A' on the data when 'K' is passed.)
 Returns
 -------
 MaskedArray
 Output view is of shape ``(self.size,)`` (or
 ``(np.ma.product(self.shape),)``).
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array([[1,2,3],[4,5,6],[7,8,9]], mask=[0] + [1,0]*4)
 >>> x
 masked_array(
 data=[[1, --, 3],
 [--, 5, --],
 [7, --, 9]],
 mask=[[False, True, False],
 [ True, False, True],
 [False, True, False]],
 fill_value=999999)
 >>> x.ravel()
 masked_array(data=[1, --, 3, --, 5, --, 7, --, 9],
 mask=[False, True, False, True, False, True, False, True,
 False],
 fill_value=999999)
 """
 # The order of _data and _mask could be different (it shouldn't be
 # normally). Passing order `K` or `A` would be incorrect.
 # So we ignore the mask memory order.
 # TODO: We don't actually support K, so use A instead. We could
 # try to guess this correct by sorting strides or deprecate.
 if order in "kKaA":
 order = "F" if self._data.flags.fnc else "C"
 r = ndarray.ravel(self._data, order=order).view(type(self))
 r._update_from(self)
 if self._mask is not nomask:
 r._mask = ndarray.ravel(self._mask, order=order).reshape(r.shape)
 else:
 r._mask = nomask
 return r
def reshape(self, *s, **kwargs):
 """
 Give a new shape to the array without changing its data.
 Returns a masked array containing the same data, but with a new shape.
 The result is a view on the original array; if this is not possible, a
 ValueError is raised.
 Parameters
 ----------
 shape : int or tuple of ints
 The new shape should be compatible with the original shape. If an
 integer is supplied, then the result will be a 1-D array of that
 length.
 order : {'C', 'F'}, optional
 Determines whether the array data should be viewed as in C
 (row-major) or FORTRAN (column-major) order.
 Returns
 -------
 reshaped_array : array
 A new view on the array.
 See Also
 --------
 reshape : Equivalent function in the masked array module.
 numpy.ndarray.reshape : Equivalent method on ndarray object.
 numpy.reshape : Equivalent function in the NumPy module.
 Notes
 -----
 The reshaping operation cannot guarantee that a copy will not be made,
 to modify the shape in place, use ``a.shape = s``
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array([[1,2],[3,4]], mask=[1,0,0,1])
 >>> x
 masked_array(
 data=[[--, 2],
 [3, --]],
 mask=[[ True, False],
 [False, True]],
 fill_value=999999)
 >>> x = x.reshape((4,1))
 >>> x
 masked_array(
 data=[[--],
 [2],
 [3],
 [--]],
 mask=[[ True],
 [False],
 [False],
 [ True]],
 fill_value=999999)
 """
 result = self._data.reshape(*s, **kwargs).view(type(self))
 result._update_from(self)
 mask = self._mask
 if mask is not nomask:
 result._mask = mask.reshape(*s, **kwargs)
 return result
def resize(self, newshape, refcheck=True, order=False):
 """
 .. warning::
 This method does nothing, except raise a ValueError exception. A
 masked array does not own its data and therefore cannot safely be
 resized in place. Use the `numpy.ma.resize` function instead.
 This method is difficult to implement safely and may be deprecated in
 future releases of NumPy.
 """
 # Note : the 'order' keyword looks broken, let's just drop it
 errmsg = "A masked array does not own its data "\
 "and therefore cannot be resized.\n" \
 "Use the numpy.ma.resize function instead."
 raise ValueError(errmsg)
def put(self, indices, values, mode='raise'):
 """
 Set storage-indexed locations to corresponding values.
 Sets self._data.flat[n] = values[n] for each n in indices.
 If `values` is shorter than `indices` then it will repeat.
 If `values` has some masked values, the initial mask is updated
 in consequence, else the corresponding values are unmasked.
 Parameters
 ----------
 indices : 1-D array_like
 Target indices, interpreted as integers.
 values : array_like
 Values to place in self._data copy at target indices.
 mode : {'raise', 'wrap', 'clip'}, optional
 Specifies how out-of-bounds indices will behave.
 'raise' : raise an error.
 'wrap' : wrap around.
 'clip' : clip to the range.
 Notes
 -----
 `values` can be a scalar or length 1 array.
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array([[1,2,3],[4,5,6],[7,8,9]], mask=[0] + [1,0]*4)
 >>> x
 masked_array(
 data=[[1, --, 3],
 [--, 5, --],
 [7, --, 9]],
 mask=[[False, True, False],
 [ True, False, True],
 [False, True, False]],
 fill_value=999999)
 >>> x.put([0,4,8],[10,20,30])
 >>> x
 masked_array(
 data=[[10, --, 3],
 [--, 20, --],
 [7, --, 30]],
 mask=[[False, True, False],
 [ True, False, True],
 [False, True, False]],
 fill_value=999999)
 >>> x.put(4,999)
 >>> x
 masked_array(
 data=[[10, --, 3],
 [--, 999, --],
 [7, --, 30]],
 mask=[[False, True, False],
 [ True, False, True],
 [False, True, False]],
 fill_value=999999)
 """
 # Hard mask: Get rid of the values/indices that fall on masked data
 if self._hardmask and self._mask is not nomask:
 mask = self._mask[indices]
 indices = narray(indices, copy=None)
 values = narray(values, copy=None, subok=True)
 values.resize(indices.shape)
 indices = indices[~mask]
 values = values[~mask]
self._data.put(indices, values, mode=mode)
# short circuit if neither self nor values are masked
 if self._mask is nomask and getmask(values) is nomask:
 return
m = getmaskarray(self)
if getmask(values) is nomask:
 m.put(indices, False, mode=mode)
 else:
 m.put(indices, values._mask, mode=mode)
 m = make_mask(m, copy=False, shrink=True)
 self._mask = m
 return
def ids(self):
 """
 Return the addresses of the data and mask areas.
 Parameters
 ----------
 None
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array([1, 2, 3], mask=[0, 1, 1])
 >>> x.ids()
 (166670640, 166659832) # may vary
 If the array has no mask, the address of `nomask` is returned. This address
 is typically not close to the data in memory:
 >>> x = np.ma.array([1, 2, 3])
 >>> x.ids()
 (166691080, 3083169284) # may vary
 """
 if self._mask is nomask:
 return (self.ctypes.data, id(nomask))
 return (self.ctypes.data, self._mask.ctypes.data)
def iscontiguous(self):
 """
 Return a boolean indicating whether the data is contiguous.
 Parameters
 ----------
 None
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array([1, 2, 3])
 >>> x.iscontiguous()
 True
 `iscontiguous` returns one of the flags of the masked array:
 >>> x.flags
 C_CONTIGUOUS : True
 F_CONTIGUOUS : True
 OWNDATA : False
 WRITEABLE : True
 ALIGNED : True
 WRITEBACKIFCOPY : False
 """
 return self.flags['CONTIGUOUS']
def all(self, axis=None, out=None, keepdims=np._NoValue):
 """
 Returns True if all elements evaluate to True.
 The output array is masked where all the values along the given axis
 are masked: if the output would have been a scalar and that all the
 values are masked, then the output is `masked`.
 Refer to `numpy.all` for full documentation.
 See Also
 --------
 numpy.ndarray.all : corresponding function for ndarrays
 numpy.all : equivalent function
 Examples
 --------
 >>> import numpy as np
 >>> np.ma.array([1,2,3]).all()
 True
 >>> a = np.ma.array([1,2,3], mask=True)
 >>> (a.all() is np.ma.masked)
 True
 """
 kwargs = {} if keepdims is np._NoValue else {'keepdims': keepdims}
mask = _check_mask_axis(self._mask, axis, **kwargs)
 if out is None:
 d = self.filled(True).all(axis=axis, **kwargs).view(type(self))
 if d.ndim:
 d.__setmask__(mask)
 elif mask:
 return masked
 return d
 self.filled(True).all(axis=axis, out=out, **kwargs)
 if isinstance(out, MaskedArray):
 if out.ndim or mask:
 out.__setmask__(mask)
 return out
def any(self, axis=None, out=None, keepdims=np._NoValue):
 """
 Returns True if any of the elements of `a` evaluate to True.
 Masked values are considered as False during computation.
 Refer to `numpy.any` for full documentation.
 See Also
 --------
 numpy.ndarray.any : corresponding function for ndarrays
 numpy.any : equivalent function
 """
 kwargs = {} if keepdims is np._NoValue else {'keepdims': keepdims}
mask = _check_mask_axis(self._mask, axis, **kwargs)
 if out is None:
 d = self.filled(False).any(axis=axis, **kwargs).view(type(self))
 if d.ndim:
 d.__setmask__(mask)
 elif mask:
 d = masked
 return d
 self.filled(False).any(axis=axis, out=out, **kwargs)
 if isinstance(out, MaskedArray):
 if out.ndim or mask:
 out.__setmask__(mask)
 return out
def nonzero(self):
 """
 Return the indices of unmasked elements that are not zero.
 Returns a tuple of arrays, one for each dimension, containing the
 indices of the non-zero elements in that dimension. The corresponding
 non-zero values can be obtained with::
 a[a.nonzero()]
 To group the indices by element, rather than dimension, use
 instead::
 np.transpose(a.nonzero())
 The result of this is always a 2d array, with a row for each non-zero
 element.
 Parameters
 ----------
 None
 Returns
 -------
 tuple_of_arrays : tuple
 Indices of elements that are non-zero.
 See Also
 --------
 numpy.nonzero :
 Function operating on ndarrays.
 flatnonzero :
 Return indices that are non-zero in the flattened version of the input
 array.
 numpy.ndarray.nonzero :
 Equivalent ndarray method.
 count_nonzero :
 Counts the number of non-zero elements in the input array.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> x = ma.array(np.eye(3))
 >>> x
 masked_array(
 data=[[1., 0., 0.],
 [0., 1., 0.],
 [0., 0., 1.]],
 mask=False,
 fill_value=1e+20)
 >>> x.nonzero()
 (array([0, 1, 2]), array([0, 1, 2]))
 Masked elements are ignored.
 >>> x[1, 1] = ma.masked
 >>> x
 masked_array(
 data=[[1.0, 0.0, 0.0],
 [0.0, --, 0.0],
 [0.0, 0.0, 1.0]],
 mask=[[False, False, False],
 [False, True, False],
 [False, False, False]],
 fill_value=1e+20)
 >>> x.nonzero()
 (array([0, 2]), array([0, 2]))
 Indices can also be grouped by element.
 >>> np.transpose(x.nonzero())
 array([[0, 0],
 [2, 2]])
 A common use for ``nonzero`` is to find the indices of an array, where
 a condition is True. Given an array `a`, the condition `a` > 3 is a
 boolean array and since False is interpreted as 0, ma.nonzero(a > 3)
 yields the indices of the `a` where the condition is true.
 >>> a = ma.array([[1,2,3],[4,5,6],[7,8,9]])
 >>> a > 3
 masked_array(
 data=[[False, False, False],
 [ True, True, True],
 [ True, True, True]],
 mask=False,
 fill_value=True)
 >>> ma.nonzero(a > 3)
 (array([1, 1, 1, 2, 2, 2]), array([0, 1, 2, 0, 1, 2]))
 The ``nonzero`` method of the condition array can also be called.
 >>> (a > 3).nonzero()
 (array([1, 1, 1, 2, 2, 2]), array([0, 1, 2, 0, 1, 2]))
 """
 return np.asarray(self.filled(0)).nonzero()
def trace(self, offset=0, axis1=0, axis2=1, dtype=None, out=None):
 """
 (this docstring should be overwritten)
 """
 # !!!: implement out + test!
 m = self._mask
 if m is nomask:
 result = super().trace(offset=offset, axis1=axis1, axis2=axis2,
 out=out)
 return result.astype(dtype)
 else:
 D = self.diagonal(offset=offset, axis1=axis1, axis2=axis2)
 return D.astype(dtype).filled(0).sum(axis=-1, out=out)
 trace.__doc__ = ndarray.trace.__doc__
def dot(self, b, out=None, strict=False):
 """
 a.dot(b, out=None)
 Masked dot product of two arrays. Note that `out` and `strict` are
 located in different positions than in `ma.dot`. In order to
 maintain compatibility with the functional version, it is
 recommended that the optional arguments be treated as keyword only.
 At some point that may be mandatory.
 Parameters
 ----------
 b : masked_array_like
 Inputs array.
 out : masked_array, optional
 Output argument. This must have the exact kind that would be
 returned if it was not used. In particular, it must have the
 right type, must be C-contiguous, and its dtype must be the
 dtype that would be returned for `ma.dot(a,b)`. This is a
 performance feature. Therefore, if these conditions are not
 met, an exception is raised, instead of attempting to be
 flexible.
 strict : bool, optional
 Whether masked data are propagated (True) or set to 0 (False)
 for the computation. Default is False. Propagating the mask
 means that if a masked value appears in a row or column, the
 whole row or column is considered masked.
 See Also
 --------
 numpy.ma.dot : equivalent function
 """
 return dot(self, b, out=out, strict=strict)
def sum(self, axis=None, dtype=None, out=None, keepdims=np._NoValue):
 """
 Return the sum of the array elements over the given axis.
 Masked elements are set to 0 internally.
 Refer to `numpy.sum` for full documentation.
 See Also
 --------
 numpy.ndarray.sum : corresponding function for ndarrays
 numpy.sum : equivalent function
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array([[1,2,3],[4,5,6],[7,8,9]], mask=[0] + [1,0]*4)
 >>> x
 masked_array(
 data=[[1, --, 3],
 [--, 5, --],
 [7, --, 9]],
 mask=[[False, True, False],
 [ True, False, True],
 [False, True, False]],
 fill_value=999999)
 >>> x.sum()
 25
 >>> x.sum(axis=1)
 masked_array(data=[4, 5, 16],
 mask=[False, False, False],
 fill_value=999999)
 >>> x.sum(axis=0)
 masked_array(data=[8, 5, 12],
 mask=[False, False, False],
 fill_value=999999)
 >>> print(type(x.sum(axis=0, dtype=np.int64)[0]))
 <class 'numpy.int64'>
 """
 kwargs = {} if keepdims is np._NoValue else {'keepdims': keepdims}
_mask = self._mask
 newmask = _check_mask_axis(_mask, axis, **kwargs)
 # No explicit output
 if out is None:
 result = self.filled(0).sum(axis, dtype=dtype, **kwargs)
 rndim = getattr(result, 'ndim', 0)
 if rndim:
 result = result.view(type(self))
 result.__setmask__(newmask)
 elif newmask:
 result = masked
 return result
 # Explicit output
 result = self.filled(0).sum(axis, dtype=dtype, out=out, **kwargs)
 if isinstance(out, MaskedArray):
 outmask = getmask(out)
 if outmask is nomask:
 outmask = out._mask = make_mask_none(out.shape)
 outmask.flat = newmask
 return out
def cumsum(self, axis=None, dtype=None, out=None):
 """
 Return the cumulative sum of the array elements over the given axis.
 Masked values are set to 0 internally during the computation.
 However, their position is saved, and the result will be masked at
 the same locations.
 Refer to `numpy.cumsum` for full documentation.
 Notes
 -----
 The mask is lost if `out` is not a valid :class:`ma.MaskedArray` !
 Arithmetic is modular when using integer types, and no error is
 raised on overflow.
 See Also
 --------
 numpy.ndarray.cumsum : corresponding function for ndarrays
 numpy.cumsum : equivalent function
 Examples
 --------
 >>> import numpy as np
 >>> marr = np.ma.array(np.arange(10), mask=[0,0,0,1,1,1,0,0,0,0])
 >>> marr.cumsum()
 masked_array(data=[0, 1, 3, --, --, --, 9, 16, 24, 33],
 mask=[False, False, False, True, True, True, False, False,
 False, False],
 fill_value=999999)
 """
 result = self.filled(0).cumsum(axis=axis, dtype=dtype, out=out)
 if out is not None:
 if isinstance(out, MaskedArray):
 out.__setmask__(self.mask)
 return out
 result = result.view(type(self))
 result.__setmask__(self._mask)
 return result
def prod(self, axis=None, dtype=None, out=None, keepdims=np._NoValue):
 """
 Return the product of the array elements over the given axis.
 Masked elements are set to 1 internally for computation.
 Refer to `numpy.prod` for full documentation.
 Notes
 -----
 Arithmetic is modular when using integer types, and no error is raised
 on overflow.
 See Also
 --------
 numpy.ndarray.prod : corresponding function for ndarrays
 numpy.prod : equivalent function
 """
 kwargs = {} if keepdims is np._NoValue else {'keepdims': keepdims}
_mask = self._mask
 newmask = _check_mask_axis(_mask, axis, **kwargs)
 # No explicit output
 if out is None:
 result = self.filled(1).prod(axis, dtype=dtype, **kwargs)
 rndim = getattr(result, 'ndim', 0)
 if rndim:
 result = result.view(type(self))
 result.__setmask__(newmask)
 elif newmask:
 result = masked
 return result
 # Explicit output
 result = self.filled(1).prod(axis, dtype=dtype, out=out, **kwargs)
 if isinstance(out, MaskedArray):
 outmask = getmask(out)
 if outmask is nomask:
 outmask = out._mask = make_mask_none(out.shape)
 outmask.flat = newmask
 return out
 product = prod
def cumprod(self, axis=None, dtype=None, out=None):
 """
 Return the cumulative product of the array elements over the given axis.
 Masked values are set to 1 internally during the computation.
 However, their position is saved, and the result will be masked at
 the same locations.
 Refer to `numpy.cumprod` for full documentation.
 Notes
 -----
 The mask is lost if `out` is not a valid MaskedArray !
 Arithmetic is modular when using integer types, and no error is
 raised on overflow.
 See Also
 --------
 numpy.ndarray.cumprod : corresponding function for ndarrays
 numpy.cumprod : equivalent function
 """
 result = self.filled(1).cumprod(axis=axis, dtype=dtype, out=out)
 if out is not None:
 if isinstance(out, MaskedArray):
 out.__setmask__(self._mask)
 return out
 result = result.view(type(self))
 result.__setmask__(self._mask)
 return result
def mean(self, axis=None, dtype=None, out=None, keepdims=np._NoValue):
 """
 Returns the average of the array elements along given axis.
 Masked entries are ignored, and result elements which are not
 finite will be masked.
 Refer to `numpy.mean` for full documentation.
 See Also
 --------
 numpy.ndarray.mean : corresponding function for ndarrays
 numpy.mean : Equivalent function
 numpy.ma.average : Weighted average.
 Examples
 --------
 >>> import numpy as np
 >>> a = np.ma.array([1,2,3], mask=[False, False, True])
 >>> a
 masked_array(data=[1, 2, --],
 mask=[False, False, True],
 fill_value=999999)
 >>> a.mean()
 1.5
 """
 kwargs = {} if keepdims is np._NoValue else {'keepdims': keepdims}
 if self._mask is nomask:
 result = super().mean(axis=axis, dtype=dtype, **kwargs)[()]
 else:
 is_float16_result = False
 if dtype is None:
 if issubclass(self.dtype.type, (ntypes.integer, ntypes.bool)):
 dtype = mu.dtype('f8')
 elif issubclass(self.dtype.type, ntypes.float16):
 dtype = mu.dtype('f4')
 is_float16_result = True
 dsum = self.sum(axis=axis, dtype=dtype, **kwargs)
 cnt = self.count(axis=axis, **kwargs)
 if cnt.shape == () and (cnt == 0):
 result = masked
 elif is_float16_result:
 result = self.dtype.type(dsum * 1. / cnt)
 else:
 result = dsum * 1. / cnt
 if out is not None:
 out.flat = result
 if isinstance(out, MaskedArray):
 outmask = getmask(out)
 if outmask is nomask:
 outmask = out._mask = make_mask_none(out.shape)
 outmask.flat = getmask(result)
 return out
 return result
def anom(self, axis=None, dtype=None):
 """
 Compute the anomalies (deviations from the arithmetic mean)
 along the given axis.
 Returns an array of anomalies, with the same shape as the input and
 where the arithmetic mean is computed along the given axis.
 Parameters
 ----------
 axis : int, optional
 Axis over which the anomalies are taken.
 The default is to use the mean of the flattened array as reference.
 dtype : dtype, optional
 Type to use in computing the variance. For arrays of integer type
 the default is float32; for arrays of float types it is the same as
 the array type.
 See Also
 --------
 mean : Compute the mean of the array.
 Examples
 --------
 >>> import numpy as np
 >>> a = np.ma.array([1,2,3])
 >>> a.anom()
 masked_array(data=[-1., 0., 1.],
 mask=False,
 fill_value=1e+20)
 """
 m = self.mean(axis, dtype)
 if not axis:
 return self - m
 else:
 return self - expand_dims(m, axis)
def var(self, axis=None, dtype=None, out=None, ddof=0,
 keepdims=np._NoValue, mean=np._NoValue):
 """
 Returns the variance of the array elements along given axis.
 Masked entries are ignored, and result elements which are not
 finite will be masked.
 Refer to `numpy.var` for full documentation.
 See Also
 --------
 numpy.ndarray.var : corresponding function for ndarrays
 numpy.var : Equivalent function
 """
 kwargs = {}
if keepdims is not np._NoValue:
 kwargs['keepdims'] = keepdims
# Easy case: nomask, business as usual
 if self._mask is nomask:
if mean is not np._NoValue:
 kwargs['mean'] = mean
ret = super().var(axis=axis, dtype=dtype, out=out, ddof=ddof,
 **kwargs)[()]
 if out is not None:
 if isinstance(out, MaskedArray):
 out.__setmask__(nomask)
 return out
 return ret
# Some data are masked, yay!
 cnt = self.count(axis=axis, **kwargs) - ddof
if mean is not np._NoValue:
 danom = self - mean
 else:
 danom = self - self.mean(axis, dtype, keepdims=True)
if iscomplexobj(self):
 danom = umath.absolute(danom) ** 2
 else:
 danom *= danom
 dvar = divide(danom.sum(axis, **kwargs), cnt).view(type(self))
 # Apply the mask if it's not a scalar
 if dvar.ndim:
 dvar._mask = mask_or(self._mask.all(axis, **kwargs), (cnt <= 0))
 dvar._update_from(self)
 elif getmask(dvar):
 # Make sure that masked is returned when the scalar is masked.
 dvar = masked
 if out is not None:
 if isinstance(out, MaskedArray):
 out.flat = 0
 out.__setmask__(True)
 elif out.dtype.kind in 'biu':
 errmsg = "Masked data information would be lost in one or "\
 "more location."
 raise MaskError(errmsg)
 else:
 out.flat = np.nan
 return out
 # In case with have an explicit output
 if out is not None:
 # Set the data
 out.flat = dvar
 # Set the mask if needed
 if isinstance(out, MaskedArray):
 out.__setmask__(dvar.mask)
 return out
 return dvar
 var.__doc__ = np.var.__doc__
def std(self, axis=None, dtype=None, out=None, ddof=0,
 keepdims=np._NoValue, mean=np._NoValue):
 """
 Returns the standard deviation of the array elements along given axis.
 Masked entries are ignored.
 Refer to `numpy.std` for full documentation.
 See Also
 --------
 numpy.ndarray.std : corresponding function for ndarrays
 numpy.std : Equivalent function
 """
 kwargs = {} if keepdims is np._NoValue else {'keepdims': keepdims}
dvar = self.var(axis, dtype, out, ddof, **kwargs)
 if dvar is not masked:
 if out is not None:
 np.power(out, 0.5, out=out, casting='unsafe')
 return out
 dvar = sqrt(dvar)
 return dvar
def round(self, decimals=0, out=None):
 """
 Return each element rounded to the given number of decimals.
 Refer to `numpy.around` for full documentation.
 See Also
 --------
 numpy.ndarray.round : corresponding function for ndarrays
 numpy.around : equivalent function
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> x = ma.array([1.35, 2.5, 1.5, 1.75, 2.25, 2.75],
 ... mask=[0, 0, 0, 1, 0, 0])
 >>> ma.round(x)
 masked_array(data=[1.0, 2.0, 2.0, --, 2.0, 3.0],
 mask=[False, False, False, True, False, False],
 fill_value=1e+20)
 """
 result = self._data.round(decimals=decimals, out=out).view(type(self))
 if result.ndim > 0:
 result._mask = self._mask
 result._update_from(self)
 elif self._mask:
 # Return masked when the scalar is masked
 result = masked
 # No explicit output: we're done
 if out is None:
 return result
 if isinstance(out, MaskedArray):
 out.__setmask__(self._mask)
 return out
def argsort(self, axis=np._NoValue, kind=None, order=None, endwith=True,
 fill_value=None, *, stable=False):
 """
 Return an ndarray of indices that sort the array along the
 specified axis. Masked values are filled beforehand to
 `fill_value`.
 Parameters
 ----------
 axis : int, optional
 Axis along which to sort. If None, the default, the flattened array
 is used.
 kind : {'quicksort', 'mergesort', 'heapsort', 'stable'}, optional
 The sorting algorithm used.
 order : str or list of str, optional
 When `a` is an array with fields defined, this argument specifies
 which fields to compare first, second, etc. Not all fields need be
 specified.
 endwith : {True, False}, optional
 Whether missing values (if any) should be treated as the largest values
 (True) or the smallest values (False)
 When the array contains unmasked values at the same extremes of the
 datatype, the ordering of these values and the masked values is
 undefined.
 fill_value : scalar or None, optional
 Value used internally for the masked values.
 If ``fill_value`` is not None, it supersedes ``endwith``.
 stable : bool, optional
 Only for compatibility with ``np.argsort``. Ignored.
 Returns
 -------
 index_array : ndarray, int
 Array of indices that sort `a` along the specified axis.
 In other words, ``a[index_array]`` yields a sorted `a`.
 See Also
 --------
 ma.MaskedArray.sort : Describes sorting algorithms used.
 lexsort : Indirect stable sort with multiple keys.
 numpy.ndarray.sort : Inplace sort.
 Notes
 -----
 See `sort` for notes on the different sorting algorithms.
 Examples
 --------
 >>> import numpy as np
 >>> a = np.ma.array([3,2,1], mask=[False, False, True])
 >>> a
 masked_array(data=[3, 2, --],
 mask=[False, False, True],
 fill_value=999999)
 >>> a.argsort()
 array([1, 0, 2])
 """
 if stable:
 raise ValueError(
 "`stable` parameter is not supported for masked arrays."
 )
# 2017-04-11, Numpy 1.13.0, gh-8701: warn on axis default
 if axis is np._NoValue:
 axis = _deprecate_argsort_axis(self)
if fill_value is None:
 if endwith:
 # nan > inf
 if np.issubdtype(self.dtype, np.floating):
 fill_value = np.nan
 else:
 fill_value = minimum_fill_value(self)
 else:
 fill_value = maximum_fill_value(self)
filled = self.filled(fill_value)
 return filled.argsort(axis=axis, kind=kind, order=order)
def argmin(self, axis=None, fill_value=None, out=None, *,
 keepdims=np._NoValue):
 """
 Return array of indices to the minimum values along the given axis.
 Parameters
 ----------
 axis : {None, integer}
 If None, the index is into the flattened array, otherwise along
 the specified axis
 fill_value : scalar or None, optional
 Value used to fill in the masked values. If None, the output of
 minimum_fill_value(self._data) is used instead.
 out : {None, array}, optional
 Array into which the result can be placed. Its type is preserved
 and it must be of the right shape to hold the output.
 Returns
 -------
 ndarray or scalar
 If multi-dimension input, returns a new ndarray of indices to the
 minimum values along the given axis. Otherwise, returns a scalar
 of index to the minimum values along the given axis.
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array(np.arange(4), mask=[1,1,0,0])
 >>> x.shape = (2,2)
 >>> x
 masked_array(
 data=[[--, --],
 [2, 3]],
 mask=[[ True, True],
 [False, False]],
 fill_value=999999)
 >>> x.argmin(axis=0, fill_value=-1)
 array([0, 0])
 >>> x.argmin(axis=0, fill_value=9)
 array([1, 1])
 """
 if fill_value is None:
 fill_value = minimum_fill_value(self)
 d = self.filled(fill_value).view(ndarray)
 keepdims = False if keepdims is np._NoValue else bool(keepdims)
 return d.argmin(axis, out=out, keepdims=keepdims)
def argmax(self, axis=None, fill_value=None, out=None, *,
 keepdims=np._NoValue):
 """
 Returns array of indices of the maximum values along the given axis.
 Masked values are treated as if they had the value fill_value.
 Parameters
 ----------
 axis : {None, integer}
 If None, the index is into the flattened array, otherwise along
 the specified axis
 fill_value : scalar or None, optional
 Value used to fill in the masked values. If None, the output of
 maximum_fill_value(self._data) is used instead.
 out : {None, array}, optional
 Array into which the result can be placed. Its type is preserved
 and it must be of the right shape to hold the output.
 Returns
 -------
 index_array : {integer_array}
 Examples
 --------
 >>> import numpy as np
 >>> a = np.arange(6).reshape(2,3)
 >>> a.argmax()
 5
 >>> a.argmax(0)
 array([1, 1, 1])
 >>> a.argmax(1)
 array([2, 2])
 """
 if fill_value is None:
 fill_value = maximum_fill_value(self._data)
 d = self.filled(fill_value).view(ndarray)
 keepdims = False if keepdims is np._NoValue else bool(keepdims)
 return d.argmax(axis, out=out, keepdims=keepdims)
def sort(self, axis=-1, kind=None, order=None, endwith=True,
 fill_value=None, *, stable=False):
 """
 Sort the array, in-place
 Parameters
 ----------
 a : array_like
 Array to be sorted.
 axis : int, optional
 Axis along which to sort. If None, the array is flattened before
 sorting. The default is -1, which sorts along the last axis.
 kind : {'quicksort', 'mergesort', 'heapsort', 'stable'}, optional
 The sorting algorithm used.
 order : list, optional
 When `a` is a structured array, this argument specifies which fields
 to compare first, second, and so on. This list does not need to
 include all of the fields.
 endwith : {True, False}, optional
 Whether missing values (if any) should be treated as the largest values
 (True) or the smallest values (False)
 When the array contains unmasked values sorting at the same extremes of the
 datatype, the ordering of these values and the masked values is
 undefined.
 fill_value : scalar or None, optional
 Value used internally for the masked values.
 If ``fill_value`` is not None, it supersedes ``endwith``.
 stable : bool, optional
 Only for compatibility with ``np.sort``. Ignored.
 See Also
 --------
 numpy.ndarray.sort : Method to sort an array in-place.
 argsort : Indirect sort.
 lexsort : Indirect stable sort on multiple keys.
 searchsorted : Find elements in a sorted array.
 Notes
 -----
 See ``sort`` for notes on the different sorting algorithms.
 Examples
 --------
 >>> import numpy as np
 >>> a = np.ma.array([1, 2, 5, 4, 3],mask=[0, 1, 0, 1, 0])
 >>> # Default
 >>> a.sort()
 >>> a
 masked_array(data=[1, 3, 5, --, --],
 mask=[False, False, False, True, True],
 fill_value=999999)
 >>> a = np.ma.array([1, 2, 5, 4, 3],mask=[0, 1, 0, 1, 0])
 >>> # Put missing values in the front
 >>> a.sort(endwith=False)
 >>> a
 masked_array(data=[--, --, 1, 3, 5],
 mask=[ True, True, False, False, False],
 fill_value=999999)
 >>> a = np.ma.array([1, 2, 5, 4, 3],mask=[0, 1, 0, 1, 0])
 >>> # fill_value takes over endwith
 >>> a.sort(endwith=False, fill_value=3)
 >>> a
 masked_array(data=[1, --, --, 3, 5],
 mask=[False, True, True, False, False],
 fill_value=999999)
 """
 if stable:
 raise ValueError(
 "`stable` parameter is not supported for masked arrays."
 )
if self._mask is nomask:
 ndarray.sort(self, axis=axis, kind=kind, order=order)
 return
if self is masked:
 return
sidx = self.argsort(axis=axis, kind=kind, order=order,
 fill_value=fill_value, endwith=endwith)
self[...] = np.take_along_axis(self, sidx, axis=axis)
def min(self, axis=None, out=None, fill_value=None, keepdims=np._NoValue):
 """
 Return the minimum along a given axis.
 Parameters
 ----------
 axis : None or int or tuple of ints, optional
 Axis along which to operate. By default, ``axis`` is None and the
 flattened input is used.
 If this is a tuple of ints, the minimum is selected over multiple
 axes, instead of a single axis or all the axes as before.
 out : array_like, optional
 Alternative output array in which to place the result. Must be of
 the same shape and buffer length as the expected output.
 fill_value : scalar or None, optional
 Value used to fill in the masked values.
 If None, use the output of `minimum_fill_value`.
 keepdims : bool, optional
 If this is set to True, the axes which are reduced are left
 in the result as dimensions with size one. With this option,
 the result will broadcast correctly against the array.
 Returns
 -------
 amin : array_like
 New array holding the result.
 If ``out`` was specified, ``out`` is returned.
 See Also
 --------
 ma.minimum_fill_value
 Returns the minimum filling value for a given datatype.
 Examples
 --------
 >>> import numpy.ma as ma
 >>> x = [[1., -2., 3.], [0.2, -0.7, 0.1]]
 >>> mask = [[1, 1, 0], [0, 0, 1]]
 >>> masked_x = ma.masked_array(x, mask)
 >>> masked_x
 masked_array(
 data=[[--, --, 3.0],
 [0.2, -0.7, --]],
 mask=[[ True, True, False],
 [False, False, True]],
 fill_value=1e+20)
 >>> ma.min(masked_x)
 -0.7
 >>> ma.min(masked_x, axis=-1)
 masked_array(data=[3.0, -0.7],
 mask=[False, False],
 fill_value=1e+20)
 >>> ma.min(masked_x, axis=0, keepdims=True)
 masked_array(data=[[0.2, -0.7, 3.0]],
 mask=[[False, False, False]],
 fill_value=1e+20)
 >>> mask = [[1, 1, 1,], [1, 1, 1]]
 >>> masked_x = ma.masked_array(x, mask)
 >>> ma.min(masked_x, axis=0)
 masked_array(data=[--, --, --],
 mask=[ True, True, True],
 fill_value=1e+20,
 dtype=float64)
 """
 kwargs = {} if keepdims is np._NoValue else {'keepdims': keepdims}
_mask = self._mask
 newmask = _check_mask_axis(_mask, axis, **kwargs)
 if fill_value is None:
 fill_value = minimum_fill_value(self)
 # No explicit output
 if out is None:
 result = self.filled(fill_value).min(
 axis=axis, out=out, **kwargs).view(type(self))
 if result.ndim:
 # Set the mask
 result.__setmask__(newmask)
 # Get rid of Infs
 if newmask.ndim:
 np.copyto(result, result.fill_value, where=newmask)
 elif newmask:
 result = masked
 return result
 # Explicit output
 self.filled(fill_value).min(axis=axis, out=out, **kwargs)
 if isinstance(out, MaskedArray):
 outmask = getmask(out)
 if outmask is nomask:
 outmask = out._mask = make_mask_none(out.shape)
 outmask.flat = newmask
 else:
 if out.dtype.kind in 'biu':
 errmsg = "Masked data information would be lost in one or more"\
 " location."
 raise MaskError(errmsg)
 np.copyto(out, np.nan, where=newmask)
 return out
def max(self, axis=None, out=None, fill_value=None, keepdims=np._NoValue):
 """
 Return the maximum along a given axis.
 Parameters
 ----------
 axis : None or int or tuple of ints, optional
 Axis along which to operate. By default, ``axis`` is None and the
 flattened input is used.
 If this is a tuple of ints, the maximum is selected over multiple
 axes, instead of a single axis or all the axes as before.
 out : array_like, optional
 Alternative output array in which to place the result. Must
 be of the same shape and buffer length as the expected output.
 fill_value : scalar or None, optional
 Value used to fill in the masked values.
 If None, use the output of maximum_fill_value().
 keepdims : bool, optional
 If this is set to True, the axes which are reduced are left
 in the result as dimensions with size one. With this option,
 the result will broadcast correctly against the array.
 Returns
 -------
 amax : array_like
 New array holding the result.
 If ``out`` was specified, ``out`` is returned.
 See Also
 --------
 ma.maximum_fill_value
 Returns the maximum filling value for a given datatype.
 Examples
 --------
 >>> import numpy.ma as ma
 >>> x = [[-1., 2.5], [4., -2.], [3., 0.]]
 >>> mask = [[0, 0], [1, 0], [1, 0]]
 >>> masked_x = ma.masked_array(x, mask)
 >>> masked_x
 masked_array(
 data=[[-1.0, 2.5],
 [--, -2.0],
 [--, 0.0]],
 mask=[[False, False],
 [ True, False],
 [ True, False]],
 fill_value=1e+20)
 >>> ma.max(masked_x)
 2.5
 >>> ma.max(masked_x, axis=0)
 masked_array(data=[-1.0, 2.5],
 mask=[False, False],
 fill_value=1e+20)
 >>> ma.max(masked_x, axis=1, keepdims=True)
 masked_array(
 data=[[2.5],
 [-2.0],
 [0.0]],
 mask=[[False],
 [False],
 [False]],
 fill_value=1e+20)
 >>> mask = [[1, 1], [1, 1], [1, 1]]
 >>> masked_x = ma.masked_array(x, mask)
 >>> ma.max(masked_x, axis=1)
 masked_array(data=[--, --, --],
 mask=[ True, True, True],
 fill_value=1e+20,
 dtype=float64)
 """
 kwargs = {} if keepdims is np._NoValue else {'keepdims': keepdims}
_mask = self._mask
 newmask = _check_mask_axis(_mask, axis, **kwargs)
 if fill_value is None:
 fill_value = maximum_fill_value(self)
 # No explicit output
 if out is None:
 result = self.filled(fill_value).max(
 axis=axis, out=out, **kwargs).view(type(self))
 if result.ndim:
 # Set the mask
 result.__setmask__(newmask)
 # Get rid of Infs
 if newmask.ndim:
 np.copyto(result, result.fill_value, where=newmask)
 elif newmask:
 result = masked
 return result
 # Explicit output
 self.filled(fill_value).max(axis=axis, out=out, **kwargs)
 if isinstance(out, MaskedArray):
 outmask = getmask(out)
 if outmask is nomask:
 outmask = out._mask = make_mask_none(out.shape)
 outmask.flat = newmask
 else:
if out.dtype.kind in 'biu':
 errmsg = "Masked data information would be lost in one or more"\
 " location."
 raise MaskError(errmsg)
 np.copyto(out, np.nan, where=newmask)
 return out
def ptp(self, axis=None, out=None, fill_value=None, keepdims=False):
 """
 Return (maximum - minimum) along the given dimension
 (i.e. peak-to-peak value).
 .. warning::
 `ptp` preserves the data type of the array. This means the
 return value for an input of signed integers with n bits
 (e.g. `np.int8`, `np.int16`, etc) is also a signed integer
 with n bits. In that case, peak-to-peak values greater than
 ``2**(n-1)-1`` will be returned as negative values. An example
 with a work-around is shown below.
 Parameters
 ----------
 axis : {None, int}, optional
 Axis along which to find the peaks. If None (default) the
 flattened array is used.
 out : {None, array_like}, optional
 Alternative output array in which to place the result. It must
 have the same shape and buffer length as the expected output
 but the type will be cast if necessary.
 fill_value : scalar or None, optional
 Value used to fill in the masked values.
 keepdims : bool, optional
 If this is set to True, the axes which are reduced are left
 in the result as dimensions with size one. With this option,
 the result will broadcast correctly against the array.
 Returns
 -------
 ptp : ndarray.
 A new array holding the result, unless ``out`` was
 specified, in which case a reference to ``out`` is returned.
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.MaskedArray([[4, 9, 2, 10],
 ... [6, 9, 7, 12]])
 >>> x.ptp(axis=1)
 masked_array(data=[8, 6],
 mask=False,
 fill_value=999999)
 >>> x.ptp(axis=0)
 masked_array(data=[2, 0, 5, 2],
 mask=False,
 fill_value=999999)
 >>> x.ptp()
 10
 This example shows that a negative value can be returned when
 the input is an array of signed integers.
 >>> y = np.ma.MaskedArray([[1, 127],
 ... [0, 127],
 ... [-1, 127],
 ... [-2, 127]], dtype=np.int8)
 >>> y.ptp(axis=1)
 masked_array(data=[ 126, 127, -128, -127],
 mask=False,
 fill_value=np.int64(999999),
 dtype=int8)
 A work-around is to use the `view()` method to view the result as
 unsigned integers with the same bit width:
 >>> y.ptp(axis=1).view(np.uint8)
 masked_array(data=[126, 127, 128, 129],
 mask=False,
 fill_value=np.uint64(999999),
 dtype=uint8)
 """
 if out is None:
 result = self.max(axis=axis, fill_value=fill_value,
 keepdims=keepdims)
 result -= self.min(axis=axis, fill_value=fill_value,
 keepdims=keepdims)
 return result
 out.flat = self.max(axis=axis, out=out, fill_value=fill_value,
 keepdims=keepdims)
 min_value = self.min(axis=axis, fill_value=fill_value,
 keepdims=keepdims)
 np.subtract(out, min_value, out=out, casting='unsafe')
 return out
def partition(self, *args, **kwargs):
 warnings.warn("Warning: 'partition' will ignore the 'mask' "
 f"of the {self.__class__.__name__}.",
 stacklevel=2)
 return super().partition(*args, **kwargs)
def argpartition(self, *args, **kwargs):
 warnings.warn("Warning: 'argpartition' will ignore the 'mask' "
 f"of the {self.__class__.__name__}.",
 stacklevel=2)
 return super().argpartition(*args, **kwargs)
def take(self, indices, axis=None, out=None, mode='raise'):
 """
 Take elements from a masked array along an axis.
 This function does the same thing as "fancy" indexing (indexing arrays
 using arrays) for masked arrays. It can be easier to use if you need
 elements along a given axis.
 Parameters
 ----------
 a : masked_array
 The source masked array.
 indices : array_like
 The indices of the values to extract. Also allow scalars for indices.
 axis : int, optional
 The axis over which to select values. By default, the flattened
 input array is used.
 out : MaskedArray, optional
 If provided, the result will be placed in this array. It should
 be of the appropriate shape and dtype. Note that `out` is always
 buffered if `mode='raise'`; use other modes for better performance.
 mode : {'raise', 'wrap', 'clip'}, optional
 Specifies how out-of-bounds indices will behave.
 * 'raise' -- raise an error (default)
 * 'wrap' -- wrap around
 * 'clip' -- clip to the range
 'clip' mode means that all indices that are too large are replaced
 by the index that addresses the last element along that axis. Note
 that this disables indexing with negative numbers.
 Returns
 -------
 out : MaskedArray
 The returned array has the same type as `a`.
 See Also
 --------
 numpy.take : Equivalent function for ndarrays.
 compress : Take elements using a boolean mask.
 take_along_axis : Take elements by matching the array and the index arrays.
 Notes
 -----
 This function behaves similarly to `numpy.take`, but it handles masked
 values. The mask is retained in the output array, and masked values
 in the input array remain masked in the output.
 Examples
 --------
 >>> import numpy as np
 >>> a = np.ma.array([4, 3, 5, 7, 6, 8], mask=[0, 0, 1, 0, 1, 0])
 >>> indices = [0, 1, 4]
 >>> np.ma.take(a, indices)
 masked_array(data=[4, 3, --],
 mask=[False, False, True],
 fill_value=999999)
 When `indices` is not one-dimensional, the output also has these dimensions:
 >>> np.ma.take(a, [[0, 1], [2, 3]])
 masked_array(data=[[4, 3],
 [--, 7]],
 mask=[[False, False],
 [ True, False]],
 fill_value=999999)
 """
 (_data, _mask) = (self._data, self._mask)
 cls = type(self)
 # Make sure the indices are not masked
 maskindices = getmask(indices)
 if maskindices is not nomask:
 indices = indices.filled(0)
 # Get the data, promoting scalars to 0d arrays with [...] so that
 # .view works correctly
 if out is None:
 out = _data.take(indices, axis=axis, mode=mode)[...].view(cls)
 else:
 np.take(_data, indices, axis=axis, mode=mode, out=out)
 # Get the mask
 if isinstance(out, MaskedArray):
 if _mask is nomask:
 outmask = maskindices
 else:
 outmask = _mask.take(indices, axis=axis, mode=mode)
 outmask |= maskindices
 out.__setmask__(outmask)
 # demote 0d arrays back to scalars, for consistency with ndarray.take
 return out[()]
# Array methods
 copy = _arraymethod('copy')
 diagonal = _arraymethod('diagonal')
 flatten = _arraymethod('flatten')
 repeat = _arraymethod('repeat')
 squeeze = _arraymethod('squeeze')
 swapaxes = _arraymethod('swapaxes')
 T = property(fget=lambda self: self.transpose())
 transpose = _arraymethod('transpose')
@property
 def mT(self):
 """
 Return the matrix-transpose of the masked array.
 The matrix transpose is the transpose of the last two dimensions, even
 if the array is of higher dimension.
 .. versionadded:: 2.0
 Returns
 -------
 result: MaskedArray
 The masked array with the last two dimensions transposed
 Raises
 ------
 ValueError
 If the array is of dimension less than 2.
 See Also
 --------
 ndarray.mT:
 Equivalent method for arrays
 """
if self.ndim < 2:
 raise ValueError("matrix transpose with ndim < 2 is undefined")
if self._mask is nomask:
 return masked_array(data=self._data.mT)
 else:
 return masked_array(data=self.data.mT, mask=self.mask.mT)
def tolist(self, fill_value=None):
 """
 Return the data portion of the masked array as a hierarchical Python list.
 Data items are converted to the nearest compatible Python type.
 Masked values are converted to `fill_value`. If `fill_value` is None,
 the corresponding entries in the output list will be ``None``.
 Parameters
 ----------
 fill_value : scalar, optional
 The value to use for invalid entries. Default is None.
 Returns
 -------
 result : list
 The Python list representation of the masked array.
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array([[1,2,3], [4,5,6], [7,8,9]], mask=[0] + [1,0]*4)
 >>> x.tolist()
 [[1, None, 3], [None, 5, None], [7, None, 9]]
 >>> x.tolist(-999)
 [[1, -999, 3], [-999, 5, -999], [7, -999, 9]]
 """
 _mask = self._mask
 # No mask ? Just return .data.tolist ?
 if _mask is nomask:
 return self._data.tolist()
 # Explicit fill_value: fill the array and get the list
 if fill_value is not None:
 return self.filled(fill_value).tolist()
 # Structured array.
 names = self.dtype.names
 if names:
 result = self._data.astype([(_, object) for _ in names])
 for n in names:
 result[n][_mask[n]] = None
 return result.tolist()
 # Standard arrays.
 if _mask is nomask:
 return [None]
 # Set temps to save time when dealing w/ marrays.
 inishape = self.shape
 result = np.array(self._data.ravel(), dtype=object)
 result[_mask.ravel()] = None
 result.shape = inishape
 return result.tolist()
def tobytes(self, fill_value=None, order='C'):
 """
 Return the array data as a string containing the raw bytes in the array.
 The array is filled with a fill value before the string conversion.
 Parameters
 ----------
 fill_value : scalar, optional
 Value used to fill in the masked values. Default is None, in which
 case `MaskedArray.fill_value` is used.
 order : {'C','F','A'}, optional
 Order of the data item in the copy. Default is 'C'.
 - 'C' -- C order (row major).
 - 'F' -- Fortran order (column major).
 - 'A' -- Any, current order of array.
 - None -- Same as 'A'.
 See Also
 --------
 numpy.ndarray.tobytes
 tolist, tofile
 Notes
 -----
 As for `ndarray.tobytes`, information about the shape, dtype, etc.,
 but also about `fill_value`, will be lost.
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array(np.array([[1, 2], [3, 4]]), mask=[[0, 1], [1, 0]])
 >>> x.tobytes()
 b'\\x01\\x00\\x00\\x00\\x00\\x00\\x00\\x00?B\\x0f\\x00\\x00\\x00\\x00\\x00?B\\x0f\\x00\\x00\\x00\\x00\\x00\\x04\\x00\\x00\\x00\\x00\\x00\\x00\\x00'
 """
 return self.filled(fill_value).tobytes(order=order)
def tofile(self, fid, sep="", format="%s"):
 """
 Save a masked array to a file in binary format.
 .. warning::
 This function is not implemented yet.
 Raises
 ------
 NotImplementedError
 When `tofile` is called.
 """
 raise NotImplementedError("MaskedArray.tofile() not implemented yet.")
def toflex(self):
 """
 Transforms a masked array into a flexible-type array.
 The flexible type array that is returned will have two fields:
 * the ``_data`` field stores the ``_data`` part of the array.
 * the ``_mask`` field stores the ``_mask`` part of the array.
 Parameters
 ----------
 None
 Returns
 -------
 record : ndarray
 A new flexible-type `ndarray` with two fields: the first element
 containing a value, the second element containing the corresponding
 mask boolean. The returned record shape matches self.shape.
 Notes
 -----
 A side-effect of transforming a masked array into a flexible `ndarray` is
 that meta information (``fill_value``, ...) will be lost.
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array([[1,2,3],[4,5,6],[7,8,9]], mask=[0] + [1,0]*4)
 >>> x
 masked_array(
 data=[[1, --, 3],
 [--, 5, --],
 [7, --, 9]],
 mask=[[False, True, False],
 [ True, False, True],
 [False, True, False]],
 fill_value=999999)
 >>> x.toflex()
 array([[(1, False), (2, True), (3, False)],
 [(4, True), (5, False), (6, True)],
 [(7, False), (8, True), (9, False)]],
 dtype=[('_data', '<i8'), ('_mask', '?')])
 """
 # Get the basic dtype.
 ddtype = self.dtype
 # Make sure we have a mask
 _mask = self._mask
 if _mask is None:
 _mask = make_mask_none(self.shape, ddtype)
 # And get its dtype
 mdtype = self._mask.dtype
record = np.ndarray(shape=self.shape,
 dtype=[('_data', ddtype), ('_mask', mdtype)])
 record['_data'] = self._data
 record['_mask'] = self._mask
 return record
 torecords = toflex
# Pickling
 def __getstate__(self):
 """Return the internal state of the masked array, for pickling
 purposes.
 """
 cf = 'CF'[self.flags.fnc]
 data_state = super().__reduce__()[2]
 return data_state + (getmaskarray(self).tobytes(cf), self._fill_value)
def __setstate__(self, state):
 """Restore the internal state of the masked array, for
 pickling purposes. ``state`` is typically the output of the
 ``__getstate__`` output, and is a 5-tuple:
 - class name
 - a tuple giving the shape of the data
 - a typecode for the data
 - a binary string for the data
 - a binary string for the mask.
 """
 (_, shp, typ, isf, raw, msk, flv) = state
 super().__setstate__((shp, typ, isf, raw))
 self._mask.__setstate__((shp, make_mask_descr(typ), isf, msk))
 self.fill_value = flv
def __reduce__(self):
 """Return a 3-tuple for pickling a MaskedArray.
 """
 return (_mareconstruct,
 (self.__class__, self._baseclass, (0,), 'b',),
 self.__getstate__())
def __deepcopy__(self, memo=None):
 from copy import deepcopy
 copied = MaskedArray.__new__(type(self), self, copy=True)
 if memo is None:
 memo = {}
 memo[id(self)] = copied
 for (k, v) in self.__dict__.items():
 copied.__dict__[k] = deepcopy(v, memo)
 # as clearly documented for np.copy(), you need to use
 # deepcopy() directly for arrays of object type that may
 # contain compound types--you cannot depend on normal
 # copy semantics to do the right thing here
 if self.dtype.hasobject:
 copied._data[...] = deepcopy(copied._data)
 return copied
def _mareconstruct(subtype, baseclass, baseshape, basetype,):
 """Internal function that builds a new MaskedArray from the
 information stored in a pickle.
 """
 _data = ndarray.__new__(baseclass, baseshape, basetype)
 _mask = ndarray.__new__(ndarray, baseshape, make_mask_descr(basetype))
 return subtype.__new__(subtype, _data, mask=_mask, dtype=basetype,)
class mvoid(MaskedArray):
 """
 Fake a 'void' object to use for masked array with structured dtypes.
 """
def __new__(self, data, mask=nomask, dtype=None, fill_value=None,
 hardmask=False, copy=False, subok=True):
 copy = None if not copy else True
 _data = np.array(data, copy=copy, subok=subok, dtype=dtype)
 _data = _data.view(self)
 _data._hardmask = hardmask
 if mask is not nomask:
 if isinstance(mask, np.void):
 _data._mask = mask
 else:
 try:
 # Mask is already a 0D array
 _data._mask = np.void(mask)
 except TypeError:
 # Transform the mask to a void
 mdtype = make_mask_descr(dtype)
 _data._mask = np.array(mask, dtype=mdtype)[()]
 if fill_value is not None:
 _data.fill_value = fill_value
 return _data
@property
 def _data(self):
 # Make sure that the _data part is a np.void
 return super()._data[()]
def __getitem__(self, indx):
 """
 Get the index.
 """
 m = self._mask
 if isinstance(m[indx], ndarray):
 # Can happen when indx is a multi-dimensional field:
 # A = ma.masked_array(data=[([0,1],)], mask=[([True,
 # False],)], dtype=[("A", ">i2", (2,))])
 # x = A[0]; y = x["A"]; then y.mask["A"].size==2
 # and we can not say masked/unmasked.
 # The result is no longer mvoid!
 # See also issue #6724.
 return masked_array(
 data=self._data[indx], mask=m[indx],
 fill_value=self._fill_value[indx],
 hard_mask=self._hardmask)
 if m is not nomask and m[indx]:
 return masked
 return self._data[indx]
def __setitem__(self, indx, value):
 self._data[indx] = value
 if self._hardmask:
 self._mask[indx] |= getattr(value, "_mask", False)
 else:
 self._mask[indx] = getattr(value, "_mask", False)
def __str__(self):
 m = self._mask
 if m is nomask:
 return str(self._data)
rdtype = _replace_dtype_fields(self._data.dtype, "O")
 data_arr = super()._data
 res = data_arr.astype(rdtype)
 _recursive_printoption(res, self._mask, masked_print_option)
 return str(res)
__repr__ = __str__
def __iter__(self):
 "Defines an iterator for mvoid"
 (_data, _mask) = (self._data, self._mask)
 if _mask is nomask:
 yield from _data
 else:
 for (d, m) in zip(_data, _mask):
 if m:
 yield masked
 else:
 yield d
def __len__(self):
 return self._data.__len__()
def filled(self, fill_value=None):
 """
 Return a copy with masked fields filled with a given value.
 Parameters
 ----------
 fill_value : array_like, optional
 The value to use for invalid entries. Can be scalar or
 non-scalar. If latter is the case, the filled array should
 be broadcastable over input array. Default is None, in
 which case the `fill_value` attribute is used instead.
 Returns
 -------
 filled_void
 A `np.void` object
 See Also
 --------
 MaskedArray.filled
 """
 return asarray(self).filled(fill_value)[()]
def tolist(self):
 """
 Transforms the mvoid object into a tuple.
 Masked fields are replaced by None.
 Returns
 -------
 returned_tuple
 Tuple of fields
 """
 _mask = self._mask
 if _mask is nomask:
 return self._data.tolist()
 result = []
 for (d, m) in zip(self._data, self._mask):
 if m:
 result.append(None)
 else:
 # .item() makes sure we return a standard Python object
 result.append(d.item())
 return tuple(result)
##############################################################################
# Shortcuts #
##############################################################################
def isMaskedArray(x):
 """
 Test whether input is an instance of MaskedArray.
 This function returns True if `x` is an instance of MaskedArray
 and returns False otherwise. Any object is accepted as input.
 Parameters
 ----------
 x : object
 Object to test.
 Returns
 -------
 result : bool
 True if `x` is a MaskedArray.
 See Also
 --------
 isMA : Alias to isMaskedArray.
 isarray : Alias to isMaskedArray.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = np.eye(3, 3)
 >>> a
 array([[ 1., 0., 0.],
 [ 0., 1., 0.],
 [ 0., 0., 1.]])
 >>> m = ma.masked_values(a, 0)
 >>> m
 masked_array(
 data=[[1.0, --, --],
 [--, 1.0, --],
 [--, --, 1.0]],
 mask=[[False, True, True],
 [ True, False, True],
 [ True, True, False]],
 fill_value=0.0)
 >>> ma.isMaskedArray(a)
 False
 >>> ma.isMaskedArray(m)
 True
 >>> ma.isMaskedArray([0, 1, 2])
 False
 """
 return isinstance(x, MaskedArray)
isarray = isMaskedArray
isMA = isMaskedArray # backward compatibility
class MaskedConstant(MaskedArray):
 # the lone np.ma.masked instance
 __singleton = None
@classmethod
 def __has_singleton(cls):
 # second case ensures `cls.__singleton` is not just a view on the
 # superclass singleton
 return cls.__singleton is not None and type(cls.__singleton) is cls
def __new__(cls):
 if not cls.__has_singleton():
 # We define the masked singleton as a float for higher precedence.
 # Note that it can be tricky sometimes w/ type comparison
 data = np.array(0.)
 mask = np.array(True)
# prevent any modifications
 data.flags.writeable = False
 mask.flags.writeable = False
# don't fall back on MaskedArray.__new__(MaskedConstant), since
 # that might confuse it - this way, the construction is entirely
 # within our control
 cls.__singleton = MaskedArray(data, mask=mask).view(cls)
return cls.__singleton
def __array_finalize__(self, obj):
 if not self.__has_singleton():
 # this handles the `.view` in __new__, which we want to copy across
 # properties normally
 return super().__array_finalize__(obj)
 elif self is self.__singleton:
 # not clear how this can happen, play it safe
 pass
 else:
 # everywhere else, we want to downcast to MaskedArray, to prevent a
 # duplicate maskedconstant.
 self.__class__ = MaskedArray
 MaskedArray.__array_finalize__(self, obj)
def __array_wrap__(self, obj, context=None, return_scalar=False):
 return self.view(MaskedArray).__array_wrap__(obj, context)
def __str__(self):
 return str(masked_print_option._display)
def __repr__(self):
 if self is MaskedConstant.__singleton:
 return 'masked'
 else:
 # it's a subclass, or something is wrong, make it obvious
 return object.__repr__(self)
def __format__(self, format_spec):
 # Replace ndarray.__format__ with the default, which supports no
 # format characters.
 # Supporting format characters is unwise here, because we do not know
 # what type the user was expecting - better to not guess.
 try:
 return object.__format__(self, format_spec)
 except TypeError:
 # 2020-03-23, NumPy 1.19.0
 warnings.warn(
 "Format strings passed to MaskedConstant are ignored,"
 " but in future may error or produce different behavior",
 FutureWarning, stacklevel=2
 )
 return object.__format__(self, "")
def __reduce__(self):
 """Override of MaskedArray's __reduce__.
 """
 return (self.__class__, ())
# inplace operations have no effect. We have to override them to avoid
 # trying to modify the readonly data and mask arrays
 def __iop__(self, other):
 return self
 __iadd__ = \
 __isub__ = \
 __imul__ = \
 __ifloordiv__ = \
 __itruediv__ = \
 __ipow__ = \
 __iop__
 del __iop__ # don't leave this around
def copy(self, *args, **kwargs):
 """ Copy is a no-op on the maskedconstant, as it is a scalar """
 # maskedconstant is a scalar, so copy doesn't need to copy. There's
 # precedent for this with `np.bool` scalars.
 return self
def __copy__(self):
 return self
def __deepcopy__(self, memo):
 return self
def __setattr__(self, attr, value):
 if not self.__has_singleton():
 # allow the singleton to be initialized
 return super().__setattr__(attr, value)
 elif self is self.__singleton:
 raise AttributeError(
 f"attributes of {self!r} are not writeable")
 else:
 # duplicate instance - we can end up here from __array_finalize__,
 # where we set the __class__ attribute
 return super().__setattr__(attr, value)
masked = masked_singleton = MaskedConstant()
masked_array = MaskedArray
def array(data, dtype=None, copy=False, order=None,
 mask=nomask, fill_value=None, keep_mask=True,
 hard_mask=False, shrink=True, subok=True, ndmin=0):
 """
 Shortcut to MaskedArray.
 The options are in a different order for convenience and backwards
 compatibility.
 """
 return MaskedArray(data, mask=mask, dtype=dtype, copy=copy,
 subok=subok, keep_mask=keep_mask,
 hard_mask=hard_mask, fill_value=fill_value,
 ndmin=ndmin, shrink=shrink, order=order)
array.__doc__ = masked_array.__doc__
def is_masked(x):
 """
 Determine whether input has masked values.
 Accepts any object as input, but always returns False unless the
 input is a MaskedArray containing masked values.
 Parameters
 ----------
 x : array_like
 Array to check for masked values.
 Returns
 -------
 result : bool
 True if `x` is a MaskedArray with masked values, False otherwise.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> x = ma.masked_equal([0, 1, 0, 2, 3], 0)
 >>> x
 masked_array(data=[--, 1, --, 2, 3],
 mask=[ True, False, True, False, False],
 fill_value=0)
 >>> ma.is_masked(x)
 True
 >>> x = ma.masked_equal([0, 1, 0, 2, 3], 42)
 >>> x
 masked_array(data=[0, 1, 0, 2, 3],
 mask=False,
 fill_value=42)
 >>> ma.is_masked(x)
 False
 Always returns False if `x` isn't a MaskedArray.
 >>> x = [False, True, False]
 >>> ma.is_masked(x)
 False
 >>> x = 'a string'
 >>> ma.is_masked(x)
 False
 """
 m = getmask(x)
 if m is nomask:
 return False
 elif m.any():
 return True
 return False
##############################################################################
# Extrema functions #
##############################################################################
class _extrema_operation(_MaskedUFunc):
 """
 Generic class for maximum/minimum functions.
 .. note::
 This is the base class for `_maximum_operation` and
 `_minimum_operation`.
 """
 def __init__(self, ufunc, compare, fill_value):
 super().__init__(ufunc)
 self.compare = compare
 self.fill_value_func = fill_value
def __call__(self, a, b):
 "Executes the call behavior."
return where(self.compare(a, b), a, b)
def reduce(self, target, axis=np._NoValue):
 "Reduce target along the given axis."
 target = narray(target, copy=None, subok=True)
 m = getmask(target)
if axis is np._NoValue and target.ndim > 1:
 name = self.__name__
 # 2017-05-06, Numpy 1.13.0: warn on axis default
 warnings.warn(
 f"In the future the default for ma.{name}.reduce will be axis=0, "
 f"not the current None, to match np.{name}.reduce. "
 "Explicitly pass 0 or None to silence this warning.",
 MaskedArrayFutureWarning, stacklevel=2)
 axis = None
if axis is not np._NoValue:
 kwargs = {'axis': axis}
 else:
 kwargs = {}
if m is nomask:
 t = self.f.reduce(target, **kwargs)
 else:
 target = target.filled(
 self.fill_value_func(target)).view(type(target))
 t = self.f.reduce(target, **kwargs)
 m = umath.logical_and.reduce(m, **kwargs)
 if hasattr(t, '_mask'):
 t._mask = m
 elif m:
 t = masked
 return t
def outer(self, a, b):
 "Return the function applied to the outer product of a and b."
 ma = getmask(a)
 mb = getmask(b)
 if ma is nomask and mb is nomask:
 m = nomask
 else:
 ma = getmaskarray(a)
 mb = getmaskarray(b)
 m = logical_or.outer(ma, mb)
 result = self.f.outer(filled(a), filled(b))
 if not isinstance(result, MaskedArray):
 result = result.view(MaskedArray)
 result._mask = m
 return result
def min(obj, axis=None, out=None, fill_value=None, keepdims=np._NoValue):
 kwargs = {} if keepdims is np._NoValue else {'keepdims': keepdims}
try:
 return obj.min(axis=axis, fill_value=fill_value, out=out, **kwargs)
 except (AttributeError, TypeError):
 # If obj doesn't have a min method, or if the method doesn't accept a
 # fill_value argument
 return asanyarray(obj).min(axis=axis, fill_value=fill_value,
 out=out, **kwargs)
min.__doc__ = MaskedArray.min.__doc__
def max(obj, axis=None, out=None, fill_value=None, keepdims=np._NoValue):
 kwargs = {} if keepdims is np._NoValue else {'keepdims': keepdims}
try:
 return obj.max(axis=axis, fill_value=fill_value, out=out, **kwargs)
 except (AttributeError, TypeError):
 # If obj doesn't have a max method, or if the method doesn't accept a
 # fill_value argument
 return asanyarray(obj).max(axis=axis, fill_value=fill_value,
 out=out, **kwargs)
max.__doc__ = MaskedArray.max.__doc__
def ptp(obj, axis=None, out=None, fill_value=None, keepdims=np._NoValue):
 kwargs = {} if keepdims is np._NoValue else {'keepdims': keepdims}
 try:
 return obj.ptp(axis, out=out, fill_value=fill_value, **kwargs)
 except (AttributeError, TypeError):
 # If obj doesn't have a ptp method or if the method doesn't accept
 # a fill_value argument
 return asanyarray(obj).ptp(axis=axis, fill_value=fill_value,
 out=out, **kwargs)
ptp.__doc__ = MaskedArray.ptp.__doc__
##############################################################################
# Definition of functions from the corresponding methods #
##############################################################################
def _frommethod(methodname: str, reversed: bool = False):
 """
 Define functions from existing MaskedArray methods.
 Parameters
 ----------
 methodname : str
 Name of the method to transform.
 reversed : bool, optional
 Whether to reverse the first two arguments of the method. Default is False.
 """
 method = getattr(MaskedArray, methodname)
 assert callable(method)
signature = inspect.signature(method)
 params = list(signature.parameters.values())
 params[0] = params[0].replace(name="a") # rename 'self' to 'a'
if reversed:
 assert len(params) >= 2
 params[0], params[1] = params[1], params[0]
def wrapper(a, b, *args, **params):
 return getattr(asanyarray(b), methodname)(a, *args, **params)
else:
 def wrapper(a, *args, **params):
 return getattr(asanyarray(a), methodname)(*args, **params)
wrapper.__signature__ = signature.replace(parameters=params)
 wrapper.__name__ = wrapper.__qualname__ = methodname
# __doc__ is None when using `python -OO ...`
 if method.__doc__ is not None:
 str_signature = f"{methodname}{signature}"
 # TODO: For methods with a docstring "Parameters" section, that do not already
 # mention `a` (see e.g. `MaskedArray.var.__doc__`), it should be inserted there.
 wrapper.__doc__ = f" {str_signature}\n{method.__doc__}"
return wrapper
all = _frommethod('all')
anomalies = anom = _frommethod('anom')
any = _frommethod('any')
argmax = _frommethod('argmax')
argmin = _frommethod('argmin')
compress = _frommethod('compress', reversed=True)
count = _frommethod('count')
cumprod = _frommethod('cumprod')
cumsum = _frommethod('cumsum')
copy = _frommethod('copy')
diagonal = _frommethod('diagonal')
harden_mask = _frommethod('harden_mask')
ids = _frommethod('ids')
maximum = _extrema_operation(umath.maximum, greater, maximum_fill_value)
mean = _frommethod('mean')
minimum = _extrema_operation(umath.minimum, less, minimum_fill_value)
nonzero = _frommethod('nonzero')
prod = _frommethod('prod')
product = _frommethod('product')
ravel = _frommethod('ravel')
repeat = _frommethod('repeat')
shrink_mask = _frommethod('shrink_mask')
soften_mask = _frommethod('soften_mask')
std = _frommethod('std')
sum = _frommethod('sum')
swapaxes = _frommethod('swapaxes')
#take = _frommethod('take')
trace = _frommethod('trace')
var = _frommethod('var')
def take(a, indices, axis=None, out=None, mode='raise'):
 """
 """
 a = masked_array(a)
 return a.take(indices, axis=axis, out=out, mode=mode)
def power(a, b, third=None):
 """
 Returns element-wise base array raised to power from second array.
 This is the masked array version of `numpy.power`. For details see
 `numpy.power`.
 See Also
 --------
 numpy.power
 Notes
 -----
 The *out* argument to `numpy.power` is not supported, `third` has to be
 None.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> x = [11.2, -3.973, 0.801, -1.41]
 >>> mask = [0, 0, 0, 1]
 >>> masked_x = ma.masked_array(x, mask)
 >>> masked_x
 masked_array(data=[11.2, -3.973, 0.801, --],
 mask=[False, False, False, True],
 fill_value=1e+20)
 >>> ma.power(masked_x, 2)
 masked_array(data=[125.43999999999998, 15.784728999999999,
 0.6416010000000001, --],
 mask=[False, False, False, True],
 fill_value=1e+20)
 >>> y = [-0.5, 2, 0, 17]
 >>> masked_y = ma.masked_array(y, mask)
 >>> masked_y
 masked_array(data=[-0.5, 2.0, 0.0, --],
 mask=[False, False, False, True],
 fill_value=1e+20)
 >>> ma.power(masked_x, masked_y)
 masked_array(data=[0.2988071523335984, 15.784728999999999, 1.0, --],
 mask=[False, False, False, True],
 fill_value=1e+20)
 """
 if third is not None:
 raise MaskError("3-argument power not supported.")
 # Get the masks
 ma = getmask(a)
 mb = getmask(b)
 m = mask_or(ma, mb)
 # Get the rawdata
 fa = getdata(a)
 fb = getdata(b)
 # Get the type of the result (so that we preserve subclasses)
 if isinstance(a, MaskedArray):
 basetype = type(a)
 else:
 basetype = MaskedArray
 # Get the result and view it as a (subclass of) MaskedArray
 with np.errstate(divide='ignore', invalid='ignore'):
 result = np.where(m, fa, umath.power(fa, fb)).view(basetype)
 result._update_from(a)
 # Find where we're in trouble w/ NaNs and Infs
 invalid = np.logical_not(np.isfinite(result.view(ndarray)))
 # Add the initial mask
 if m is not nomask:
 if not result.ndim:
 return masked
 result._mask = np.logical_or(m, invalid)
 # Fix the invalid parts
 if invalid.any():
 if not result.ndim:
 return masked
 elif result._mask is nomask:
 result._mask = invalid
 result._data[invalid] = result.fill_value
 return result
def argsort(a, axis=np._NoValue, kind=None, order=None, endwith=True,
 fill_value=None, *, stable=None):
 "Function version of the eponymous method."
 a = np.asanyarray(a)
# 2017-04-11, Numpy 1.13.0, gh-8701: warn on axis default
 if axis is np._NoValue:
 axis = _deprecate_argsort_axis(a)
if isinstance(a, MaskedArray):
 return a.argsort(axis=axis, kind=kind, order=order, endwith=endwith,
 fill_value=fill_value, stable=None)
 else:
 return a.argsort(axis=axis, kind=kind, order=order, stable=None)
argsort.__doc__ = MaskedArray.argsort.__doc__
def sort(a, axis=-1, kind=None, order=None, endwith=True, fill_value=None, *,
 stable=None):
 """
 Return a sorted copy of the masked array.
 Equivalent to creating a copy of the array
 and applying the MaskedArray ``sort()`` method.
 Refer to ``MaskedArray.sort`` for the full documentation
 See Also
 --------
 MaskedArray.sort : equivalent method
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> x = [11.2, -3.973, 0.801, -1.41]
 >>> mask = [0, 0, 0, 1]
 >>> masked_x = ma.masked_array(x, mask)
 >>> masked_x
 masked_array(data=[11.2, -3.973, 0.801, --],
 mask=[False, False, False, True],
 fill_value=1e+20)
 >>> ma.sort(masked_x)
 masked_array(data=[-3.973, 0.801, 11.2, --],
 mask=[False, False, False, True],
 fill_value=1e+20)
 """
 a = np.array(a, copy=True, subok=True)
 if axis is None:
 a = a.flatten()
 axis = 0
if isinstance(a, MaskedArray):
 a.sort(axis=axis, kind=kind, order=order, endwith=endwith,
 fill_value=fill_value, stable=stable)
 else:
 a.sort(axis=axis, kind=kind, order=order, stable=stable)
 return a
def compressed(x):
 """
 Return all the non-masked data as a 1-D array.
 This function is equivalent to calling the "compressed" method of a
 `ma.MaskedArray`, see `ma.MaskedArray.compressed` for details.
 See Also
 --------
 ma.MaskedArray.compressed : Equivalent method.
 Examples
 --------
 >>> import numpy as np
 Create an array with negative values masked:
 >>> import numpy as np
 >>> x = np.array([[1, -1, 0], [2, -1, 3], [7, 4, -1]])
 >>> masked_x = np.ma.masked_array(x, mask=x < 0)
 >>> masked_x
 masked_array(
 data=[[1, --, 0],
 [2, --, 3],
 [7, 4, --]],
 mask=[[False, True, False],
 [False, True, False],
 [False, False, True]],
 fill_value=999999)
 Compress the masked array into a 1-D array of non-masked values:
 >>> np.ma.compressed(masked_x)
 array([1, 0, 2, 3, 7, 4])
 """
 return asanyarray(x).compressed()
def concatenate(arrays, axis=0):
 """
 Concatenate a sequence of arrays along the given axis.
 Parameters
 ----------
 arrays : sequence of array_like
 The arrays must have the same shape, except in the dimension
 corresponding to `axis` (the first, by default).
 axis : int, optional
 The axis along which the arrays will be joined. Default is 0.
 Returns
 -------
 result : MaskedArray
 The concatenated array with any masked entries preserved.
 See Also
 --------
 numpy.concatenate : Equivalent function in the top-level NumPy module.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = ma.arange(3)
 >>> a[1] = ma.masked
 >>> b = ma.arange(2, 5)
 >>> a
 masked_array(data=[0, --, 2],
 mask=[False, True, False],
 fill_value=999999)
 >>> b
 masked_array(data=[2, 3, 4],
 mask=False,
 fill_value=999999)
 >>> ma.concatenate([a, b])
 masked_array(data=[0, --, 2, 2, 3, 4],
 mask=[False, True, False, False, False, False],
 fill_value=999999)
 """
 d = np.concatenate([getdata(a) for a in arrays], axis)
 rcls = get_masked_subclass(*arrays)
 data = d.view(rcls)
 # Check whether one of the arrays has a non-empty mask.
 for x in arrays:
 if getmask(x) is not nomask:
 break
 else:
 return data
 # OK, so we have to concatenate the masks
 dm = np.concatenate([getmaskarray(a) for a in arrays], axis)
 dm = dm.reshape(d.shape)
# If we decide to keep a '_shrinkmask' option, we want to check that
 # all of them are True, and then check for dm.any()
 data._mask = _shrink_mask(dm)
 return data
def diag(v, k=0):
 """
 Extract a diagonal or construct a diagonal array.
 This function is the equivalent of `numpy.diag` that takes masked
 values into account, see `numpy.diag` for details.
 See Also
 --------
 numpy.diag : Equivalent function for ndarrays.
 Examples
 --------
 >>> import numpy as np
 Create an array with negative values masked:
 >>> import numpy as np
 >>> x = np.array([[11.2, -3.973, 18], [0.801, -1.41, 12], [7, 33, -12]])
 >>> masked_x = np.ma.masked_array(x, mask=x < 0)
 >>> masked_x
 masked_array(
 data=[[11.2, --, 18.0],
 [0.801, --, 12.0],
 [7.0, 33.0, --]],
 mask=[[False, True, False],
 [False, True, False],
 [False, False, True]],
 fill_value=1e+20)
 Isolate the main diagonal from the masked array:
 >>> np.ma.diag(masked_x)
 masked_array(data=[11.2, --, --],
 mask=[False, True, True],
 fill_value=1e+20)
 Isolate the first diagonal below the main diagonal:
 >>> np.ma.diag(masked_x, -1)
 masked_array(data=[0.801, 33.0],
 mask=[False, False],
 fill_value=1e+20)
 """
 output = np.diag(v, k).view(MaskedArray)
 if getmask(v) is not nomask:
 output._mask = np.diag(v._mask, k)
 return output
def left_shift(a, n):
 """
 Shift the bits of an integer to the left.
 This is the masked array version of `numpy.left_shift`, for details
 see that function.
 See Also
 --------
 numpy.left_shift
 Examples
 --------
 Shift with a masked array:
 >>> arr = np.ma.array([10, 20, 30], mask=[False, True, False])
 >>> np.ma.left_shift(arr, 1)
 masked_array(data=[20, --, 60],
 mask=[False, True, False],
 fill_value=999999)
 Large shift:
 >>> np.ma.left_shift(10, 10)
 masked_array(data=10240,
 mask=False,
 fill_value=999999)
 Shift with a scalar and an array:
 >>> scalar = 10
 >>> arr = np.ma.array([1, 2, 3], mask=[False, True, False])
 >>> np.ma.left_shift(scalar, arr)
 masked_array(data=[20, --, 80],
 mask=[False, True, False],
 fill_value=999999)
 """
 m = getmask(a)
 if m is nomask:
 d = umath.left_shift(filled(a), n)
 return masked_array(d)
 else:
 d = umath.left_shift(filled(a, 0), n)
 return masked_array(d, mask=m)
def right_shift(a, n):
 """
 Shift the bits of an integer to the right.
 This is the masked array version of `numpy.right_shift`, for details
 see that function.
 See Also
 --------
 numpy.right_shift
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> x = [11, 3, 8, 1]
 >>> mask = [0, 0, 0, 1]
 >>> masked_x = ma.masked_array(x, mask)
 >>> masked_x
 masked_array(data=[11, 3, 8, --],
 mask=[False, False, False, True],
 fill_value=999999)
 >>> ma.right_shift(masked_x,1)
 masked_array(data=[5, 1, 4, --],
 mask=[False, False, False, True],
 fill_value=999999)
 """
 m = getmask(a)
 if m is nomask:
 d = umath.right_shift(filled(a), n)
 return masked_array(d)
 else:
 d = umath.right_shift(filled(a, 0), n)
 return masked_array(d, mask=m)
def put(a, indices, values, mode='raise'):
 """
 Set storage-indexed locations to corresponding values.
 This function is equivalent to `MaskedArray.put`, see that method
 for details.
 See Also
 --------
 MaskedArray.put
 Examples
 --------
 Putting values in a masked array:
 >>> a = np.ma.array([1, 2, 3, 4], mask=[False, True, False, False])
 >>> np.ma.put(a, [1, 3], [10, 30])
 >>> a
 masked_array(data=[ 1, 10, 3, 30],
 mask=False,
 fill_value=999999)
 Using put with a 2D array:
 >>> b = np.ma.array([[1, 2], [3, 4]], mask=[[False, True], [False, False]])
 >>> np.ma.put(b, [[0, 1], [1, 0]], [[10, 20], [30, 40]])
 >>> b
 masked_array(
 data=[[40, 30],
 [ 3, 4]],
 mask=False,
 fill_value=999999)
 """
 # We can't use 'frommethod', the order of arguments is different
 try:
 return a.put(indices, values, mode=mode)
 except AttributeError:
 return np.asarray(a).put(indices, values, mode=mode)
def putmask(a, mask, values): # , mode='raise'):
 """
 Changes elements of an array based on conditional and input values.
 This is the masked array version of `numpy.putmask`, for details see
 `numpy.putmask`.
 See Also
 --------
 numpy.putmask
 Notes
 -----
 Using a masked array as `values` will **not** transform a `ndarray` into
 a `MaskedArray`.
 Examples
 --------
 >>> import numpy as np
 >>> arr = [[1, 2], [3, 4]]
 >>> mask = [[1, 0], [0, 0]]
 >>> x = np.ma.array(arr, mask=mask)
 >>> np.ma.putmask(x, x < 4, 10*x)
 >>> x
 masked_array(
 data=[[--, 20],
 [30, 4]],
 mask=[[ True, False],
 [False, False]],
 fill_value=999999)
 >>> x.data
 array([[10, 20],
 [30, 4]])
 """
 # We can't use 'frommethod', the order of arguments is different
 if not isinstance(a, MaskedArray):
 a = a.view(MaskedArray)
 (valdata, valmask) = (getdata(values), getmask(values))
 if getmask(a) is nomask:
 if valmask is not nomask:
 a._sharedmask = True
 a._mask = make_mask_none(a.shape, a.dtype)
 np.copyto(a._mask, valmask, where=mask)
 elif a._hardmask:
 if valmask is not nomask:
 m = a._mask.copy()
 np.copyto(m, valmask, where=mask)
 a.mask |= m
 else:
 if valmask is nomask:
 valmask = getmaskarray(values)
 np.copyto(a._mask, valmask, where=mask)
 np.copyto(a._data, valdata, where=mask)
def transpose(a, axes=None):
 """
 Permute the dimensions of an array.
 This function is exactly equivalent to `numpy.transpose`.
 See Also
 --------
 numpy.transpose : Equivalent function in top-level NumPy module.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> x = ma.arange(4).reshape((2,2))
 >>> x[1, 1] = ma.masked
 >>> x
 masked_array(
 data=[[0, 1],
 [2, --]],
 mask=[[False, False],
 [False, True]],
 fill_value=999999)
 >>> ma.transpose(x)
 masked_array(
 data=[[0, 2],
 [1, --]],
 mask=[[False, False],
 [False, True]],
 fill_value=999999)
 """
 # We can't use 'frommethod', as 'transpose' doesn't take keywords
 try:
 return a.transpose(axes)
 except AttributeError:
 return np.asarray(a).transpose(axes).view(MaskedArray)
def reshape(a, new_shape, order='C'):
 """
 Returns an array containing the same data with a new shape.
 Refer to `MaskedArray.reshape` for full documentation.
 See Also
 --------
 MaskedArray.reshape : equivalent function
 Examples
 --------
 Reshaping a 1-D array:
 >>> a = np.ma.array([1, 2, 3, 4])
 >>> np.ma.reshape(a, (2, 2))
 masked_array(
 data=[[1, 2],
 [3, 4]],
 mask=False,
 fill_value=999999)
 Reshaping a 2-D array:
 >>> b = np.ma.array([[1, 2], [3, 4]])
 >>> np.ma.reshape(b, (1, 4))
 masked_array(data=[[1, 2, 3, 4]],
 mask=False,
 fill_value=999999)
 Reshaping a 1-D array with a mask:
 >>> c = np.ma.array([1, 2, 3, 4], mask=[False, True, False, False])
 >>> np.ma.reshape(c, (2, 2))
 masked_array(
 data=[[1, --],
 [3, 4]],
 mask=[[False, True],
 [False, False]],
 fill_value=999999)
 """
 # We can't use 'frommethod', it whine about some parameters. Dmmit.
 try:
 return a.reshape(new_shape, order=order)
 except AttributeError:
 _tmp = np.asarray(a).reshape(new_shape, order=order)
 return _tmp.view(MaskedArray)
def resize(x, new_shape):
 """
 Return a new masked array with the specified size and shape.
 This is the masked equivalent of the `numpy.resize` function. The new
 array is filled with repeated copies of `x` (in the order that the
 data are stored in memory). If `x` is masked, the new array will be
 masked, and the new mask will be a repetition of the old one.
 See Also
 --------
 numpy.resize : Equivalent function in the top level NumPy module.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = ma.array([[1, 2] ,[3, 4]])
 >>> a[0, 1] = ma.masked
 >>> a
 masked_array(
 data=[[1, --],
 [3, 4]],
 mask=[[False, True],
 [False, False]],
 fill_value=999999)
 >>> np.resize(a, (3, 3))
 masked_array(
 data=[[1, 2, 3],
 [4, 1, 2],
 [3, 4, 1]],
 mask=False,
 fill_value=999999)
 >>> ma.resize(a, (3, 3))
 masked_array(
 data=[[1, --, 3],
 [4, 1, --],
 [3, 4, 1]],
 mask=[[False, True, False],
 [False, False, True],
 [False, False, False]],
 fill_value=999999)
 A MaskedArray is always returned, regardless of the input type.
 >>> a = np.array([[1, 2] ,[3, 4]])
 >>> ma.resize(a, (3, 3))
 masked_array(
 data=[[1, 2, 3],
 [4, 1, 2],
 [3, 4, 1]],
 mask=False,
 fill_value=999999)
 """
 # We can't use _frommethods here, as N.resize is notoriously whiny.
 m = getmask(x)
 if m is not nomask:
 m = np.resize(m, new_shape)
 result = np.resize(x, new_shape).view(get_masked_subclass(x))
 if result.ndim:
 result._mask = m
 return result
def ndim(obj):
 """
 maskedarray version of the numpy function.
 """
 return np.ndim(getdata(obj))
ndim.__doc__ = np.ndim.__doc__
def shape(obj):
 "maskedarray version of the numpy function."
 return np.shape(getdata(obj))
shape.__doc__ = np.shape.__doc__
def size(obj, axis=None):
 "maskedarray version of the numpy function."
 return np.size(getdata(obj), axis)
size.__doc__ = np.size.__doc__
def diff(a, /, n=1, axis=-1, prepend=np._NoValue, append=np._NoValue):
 """
 Calculate the n-th discrete difference along the given axis.
 The first difference is given by ``out[i] = a[i+1] - a[i]`` along
 the given axis, higher differences are calculated by using `diff`
 recursively.
 Preserves the input mask.
 Parameters
 ----------
 a : array_like
 Input array
 n : int, optional
 The number of times values are differenced. If zero, the input
 is returned as-is.
 axis : int, optional
 The axis along which the difference is taken, default is the
 last axis.
 prepend, append : array_like, optional
 Values to prepend or append to `a` along axis prior to
 performing the difference. Scalar values are expanded to
 arrays with length 1 in the direction of axis and the shape
 of the input array in along all other axes. Otherwise the
 dimension and shape must match `a` except along axis.
 Returns
 -------
 diff : MaskedArray
 The n-th differences. The shape of the output is the same as `a`
 except along `axis` where the dimension is smaller by `n`. The
 type of the output is the same as the type of the difference
 between any two elements of `a`. This is the same as the type of
 `a` in most cases. A notable exception is `datetime64`, which
 results in a `timedelta64` output array.
 See Also
 --------
 numpy.diff : Equivalent function in the top-level NumPy module.
 Notes
 -----
 Type is preserved for boolean arrays, so the result will contain
 `False` when consecutive elements are the same and `True` when they
 differ.
 For unsigned integer arrays, the results will also be unsigned. This
 should not be surprising, as the result is consistent with
 calculating the difference directly:
 >>> u8_arr = np.array([1, 0], dtype=np.uint8)
 >>> np.ma.diff(u8_arr)
 masked_array(data=[255],
 mask=False,
 fill_value=np.uint64(999999),
 dtype=uint8)
 >>> u8_arr[1,...] - u8_arr[0,...]
 np.uint8(255)
 If this is not desirable, then the array should be cast to a larger
 integer type first:
 >>> i16_arr = u8_arr.astype(np.int16)
 >>> np.ma.diff(i16_arr)
 masked_array(data=[-1],
 mask=False,
 fill_value=np.int64(999999),
 dtype=int16)
 Examples
 --------
 >>> import numpy as np
 >>> a = np.array([1, 2, 3, 4, 7, 0, 2, 3])
 >>> x = np.ma.masked_where(a < 2, a)
 >>> np.ma.diff(x)
 masked_array(data=[--, 1, 1, 3, --, --, 1],
 mask=[ True, False, False, False, True, True, False],
 fill_value=999999)
 >>> np.ma.diff(x, n=2)
 masked_array(data=[--, 0, 2, --, --, --],
 mask=[ True, False, False, True, True, True],
 fill_value=999999)
 >>> a = np.array([[1, 3, 1, 5, 10], [0, 1, 5, 6, 8]])
 >>> x = np.ma.masked_equal(a, value=1)
 >>> np.ma.diff(x)
 masked_array(
 data=[[--, --, --, 5],
 [--, --, 1, 2]],
 mask=[[ True, True, True, False],
 [ True, True, False, False]],
 fill_value=1)
 >>> np.ma.diff(x, axis=0)
 masked_array(data=[[--, --, --, 1, -2]],
 mask=[[ True, True, True, False, False]],
 fill_value=1)
 """
 if n == 0:
 return a
 if n < 0:
 raise ValueError("order must be non-negative but got " + repr(n))
a = np.ma.asanyarray(a)
 if a.ndim == 0:
 raise ValueError(
 "diff requires input that is at least one dimensional"
 )
combined = []
 if prepend is not np._NoValue:
 prepend = np.ma.asanyarray(prepend)
 if prepend.ndim == 0:
 shape = list(a.shape)
 shape[axis] = 1
 prepend = np.broadcast_to(prepend, tuple(shape))
 combined.append(prepend)
combined.append(a)
if append is not np._NoValue:
 append = np.ma.asanyarray(append)
 if append.ndim == 0:
 shape = list(a.shape)
 shape[axis] = 1
 append = np.broadcast_to(append, tuple(shape))
 combined.append(append)
if len(combined) > 1:
 a = np.ma.concatenate(combined, axis)
# GH 22465 np.diff without prepend/append preserves the mask
 return np.diff(a, n, axis)
##############################################################################
# Extra functions #
##############################################################################
def where(condition, x=_NoValue, y=_NoValue):
 """
 Return a masked array with elements from `x` or `y`, depending on condition.
 .. note::
 When only `condition` is provided, this function is identical to
 `nonzero`. The rest of this documentation covers only the case where
 all three arguments are provided.
 Parameters
 ----------
 condition : array_like, bool
 Where True, yield `x`, otherwise yield `y`.
 x, y : array_like, optional
 Values from which to choose. `x`, `y` and `condition` need to be
 broadcastable to some shape.
 Returns
 -------
 out : MaskedArray
 An masked array with `masked` elements where the condition is masked,
 elements from `x` where `condition` is True, and elements from `y`
 elsewhere.
 See Also
 --------
 numpy.where : Equivalent function in the top-level NumPy module.
 nonzero : The function that is called when x and y are omitted
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array(np.arange(9.).reshape(3, 3), mask=[[0, 1, 0],
 ... [1, 0, 1],
 ... [0, 1, 0]])
 >>> x
 masked_array(
 data=[[0.0, --, 2.0],
 [--, 4.0, --],
 [6.0, --, 8.0]],
 mask=[[False, True, False],
 [ True, False, True],
 [False, True, False]],
 fill_value=1e+20)
 >>> np.ma.where(x > 5, x, -3.1416)
 masked_array(
 data=[[-3.1416, --, -3.1416],
 [--, -3.1416, --],
 [6.0, --, 8.0]],
 mask=[[False, True, False],
 [ True, False, True],
 [False, True, False]],
 fill_value=1e+20)
 """
# handle the single-argument case
 missing = (x is _NoValue, y is _NoValue).count(True)
 if missing == 1:
 raise ValueError("Must provide both 'x' and 'y' or neither.")
 if missing == 2:
 return nonzero(condition)
# we only care if the condition is true - false or masked pick y
 cf = filled(condition, False)
 xd = getdata(x)
 yd = getdata(y)
# we need the full arrays here for correct final dimensions
 cm = getmaskarray(condition)
 xm = getmaskarray(x)
 ym = getmaskarray(y)
# deal with the fact that masked.dtype == float64, but we don't actually
 # want to treat it as that.
 if x is masked and y is not masked:
 xd = np.zeros((), dtype=yd.dtype)
 xm = np.ones((), dtype=ym.dtype)
 elif y is masked and x is not masked:
 yd = np.zeros((), dtype=xd.dtype)
 ym = np.ones((), dtype=xm.dtype)
data = np.where(cf, xd, yd)
 mask = np.where(cf, xm, ym)
 mask = np.where(cm, np.ones((), dtype=mask.dtype), mask)
# collapse the mask, for backwards compatibility
 mask = _shrink_mask(mask)
return masked_array(data, mask=mask)
def choose(indices, choices, out=None, mode='raise'):
 """
 Use an index array to construct a new array from a list of choices.
 Given an array of integers and a list of n choice arrays, this method
 will create a new array that merges each of the choice arrays. Where a
 value in `index` is i, the new array will have the value that choices[i]
 contains in the same place.
 Parameters
 ----------
 indices : ndarray of ints
 This array must contain integers in ``[0, n-1]``, where n is the
 number of choices.
 choices : sequence of arrays
 Choice arrays. The index array and all of the choices should be
 broadcastable to the same shape.
 out : array, optional
 If provided, the result will be inserted into this array. It should
 be of the appropriate shape and `dtype`.
 mode : {'raise', 'wrap', 'clip'}, optional
 Specifies how out-of-bounds indices will behave.
 * 'raise' : raise an error
 * 'wrap' : wrap around
 * 'clip' : clip to the range
 Returns
 -------
 merged_array : array
 See Also
 --------
 choose : equivalent function
 Examples
 --------
 >>> import numpy as np
 >>> choice = np.array([[1,1,1], [2,2,2], [3,3,3]])
 >>> a = np.array([2, 1, 0])
 >>> np.ma.choose(a, choice)
 masked_array(data=[3, 2, 1],
 mask=False,
 fill_value=999999)
 """
 def fmask(x):
 "Returns the filled array, or True if masked."
 if x is masked:
 return True
 return filled(x)
def nmask(x):
 "Returns the mask, True if ``masked``, False if ``nomask``."
 if x is masked:
 return True
 return getmask(x)
 # Get the indices.
 c = filled(indices, 0)
 # Get the masks.
 masks = [nmask(x) for x in choices]
 data = [fmask(x) for x in choices]
 # Construct the mask
 outputmask = np.choose(c, masks, mode=mode)
 outputmask = make_mask(mask_or(outputmask, getmask(indices)),
 copy=False, shrink=True)
 # Get the choices.
 d = np.choose(c, data, mode=mode, out=out).view(MaskedArray)
 if out is not None:
 if isinstance(out, MaskedArray):
 out.__setmask__(outputmask)
 return out
 d.__setmask__(outputmask)
 return d
def round_(a, decimals=0, out=None):
 """
 Return a copy of a, rounded to 'decimals' places.
 When 'decimals' is negative, it specifies the number of positions
 to the left of the decimal point. The real and imaginary parts of
 complex numbers are rounded separately. Nothing is done if the
 array is not of float type and 'decimals' is greater than or equal
 to 0.
 Parameters
 ----------
 decimals : int
 Number of decimals to round to. May be negative.
 out : array_like
 Existing array to use for output.
 If not given, returns a default copy of a.
 Notes
 -----
 If out is given and does not have a mask attribute, the mask of a
 is lost!
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> x = [11.2, -3.973, 0.801, -1.41]
 >>> mask = [0, 0, 0, 1]
 >>> masked_x = ma.masked_array(x, mask)
 >>> masked_x
 masked_array(data=[11.2, -3.973, 0.801, --],
 mask=[False, False, False, True],
 fill_value=1e+20)
 >>> ma.round_(masked_x)
 masked_array(data=[11.0, -4.0, 1.0, --],
 mask=[False, False, False, True],
 fill_value=1e+20)
 >>> ma.round(masked_x, decimals=1)
 masked_array(data=[11.2, -4.0, 0.8, --],
 mask=[False, False, False, True],
 fill_value=1e+20)
 >>> ma.round_(masked_x, decimals=-1)
 masked_array(data=[10.0, -0.0, 0.0, --],
 mask=[False, False, False, True],
 fill_value=1e+20)
 """
 if out is None:
 return np.round(a, decimals, out)
 else:
 np.round(getdata(a), decimals, out)
 if hasattr(out, '_mask'):
 out._mask = getmask(a)
 return out
round = round_
def _mask_propagate(a, axis):
 """
 Mask whole 1-d vectors of an array that contain masked values.
 """
 a = array(a, subok=False)
 m = getmask(a)
 if m is nomask or not m.any() or axis is None:
 return a
 a._mask = a._mask.copy()
 axes = normalize_axis_tuple(axis, a.ndim)
 for ax in axes:
 a._mask |= m.any(axis=ax, keepdims=True)
 return a
# Include masked dot here to avoid import problems in getting it from
# extras.py. Note that it is not included in __all__, but rather exported
# from extras in order to avoid backward compatibility problems.
def dot(a, b, strict=False, out=None):
 """
 Return the dot product of two arrays.
 This function is the equivalent of `numpy.dot` that takes masked values
 into account. Note that `strict` and `out` are in different position
 than in the method version. In order to maintain compatibility with the
 corresponding method, it is recommended that the optional arguments be
 treated as keyword only. At some point that may be mandatory.
 Parameters
 ----------
 a, b : masked_array_like
 Inputs arrays.
 strict : bool, optional
 Whether masked data are propagated (True) or set to 0 (False) for
 the computation. Default is False. Propagating the mask means that
 if a masked value appears in a row or column, the whole row or
 column is considered masked.
 out : masked_array, optional
 Output argument. This must have the exact kind that would be returned
 if it was not used. In particular, it must have the right type, must be
 C-contiguous, and its dtype must be the dtype that would be returned
 for `dot(a,b)`. This is a performance feature. Therefore, if these
 conditions are not met, an exception is raised, instead of attempting
 to be flexible.
 See Also
 --------
 numpy.dot : Equivalent function for ndarrays.
 Examples
 --------
 >>> import numpy as np
 >>> a = np.ma.array([[1, 2, 3], [4, 5, 6]], mask=[[1, 0, 0], [0, 0, 0]])
 >>> b = np.ma.array([[1, 2], [3, 4], [5, 6]], mask=[[1, 0], [0, 0], [0, 0]])
 >>> np.ma.dot(a, b)
 masked_array(
 data=[[21, 26],
 [45, 64]],
 mask=[[False, False],
 [False, False]],
 fill_value=999999)
 >>> np.ma.dot(a, b, strict=True)
 masked_array(
 data=[[--, --],
 [--, 64]],
 mask=[[ True, True],
 [ True, False]],
 fill_value=999999)
 """
 if strict is True:
 if np.ndim(a) == 0 or np.ndim(b) == 0:
 pass
 elif b.ndim == 1:
 a = _mask_propagate(a, a.ndim - 1)
 b = _mask_propagate(b, b.ndim - 1)
 else:
 a = _mask_propagate(a, a.ndim - 1)
 b = _mask_propagate(b, b.ndim - 2)
 am = ~getmaskarray(a)
 bm = ~getmaskarray(b)
if out is None:
 d = np.dot(filled(a, 0), filled(b, 0))
 m = ~np.dot(am, bm)
 if np.ndim(d) == 0:
 d = np.asarray(d)
 r = d.view(get_masked_subclass(a, b))
 r.__setmask__(m)
 return r
 else:
 d = np.dot(filled(a, 0), filled(b, 0), out._data)
 if out.mask.shape != d.shape:
 out._mask = np.empty(d.shape, MaskType)
 np.dot(am, bm, out._mask)
 np.logical_not(out._mask, out._mask)
 return out
def inner(a, b):
 """
 Returns the inner product of a and b for arrays of floating point types.
 Like the generic NumPy equivalent the product sum is over the last dimension
 of a and b. The first argument is not conjugated.
 """
 fa = filled(a, 0)
 fb = filled(b, 0)
 if fa.ndim == 0:
 fa.shape = (1,)
 if fb.ndim == 0:
 fb.shape = (1,)
 return np.inner(fa, fb).view(MaskedArray)
inner.__doc__ = doc_note(np.inner.__doc__,
 "Masked values are replaced by 0.")
innerproduct = inner
def outer(a, b):
 "maskedarray version of the numpy function."
 fa = filled(a, 0).ravel()
 fb = filled(b, 0).ravel()
 d = np.outer(fa, fb)
 ma = getmask(a)
 mb = getmask(b)
 if ma is nomask and mb is nomask:
 return masked_array(d)
 ma = getmaskarray(a)
 mb = getmaskarray(b)
 m = make_mask(1 - np.outer(1 - ma, 1 - mb), copy=False)
 return masked_array(d, mask=m)
outer.__doc__ = doc_note(np.outer.__doc__,
 "Masked values are replaced by 0.")
outerproduct = outer
def _convolve_or_correlate(f, a, v, mode, propagate_mask):
 """
 Helper function for ma.correlate and ma.convolve
 """
 if propagate_mask:
 # results which are contributed to by either item in any pair being invalid
 mask = (
 f(getmaskarray(a), np.ones(np.shape(v), dtype=bool), mode=mode)
 | f(np.ones(np.shape(a), dtype=bool), getmaskarray(v), mode=mode)
 )
 data = f(getdata(a), getdata(v), mode=mode)
 else:
 # results which are not contributed to by any pair of valid elements
 mask = ~f(~getmaskarray(a), ~getmaskarray(v), mode=mode)
 data = f(filled(a, 0), filled(v, 0), mode=mode)
return masked_array(data, mask=mask)
def correlate(a, v, mode='valid', propagate_mask=True):
 """
 Cross-correlation of two 1-dimensional sequences.
 Parameters
 ----------
 a, v : array_like
 Input sequences.
 mode : {'valid', 'same', 'full'}, optional
 Refer to the `np.convolve` docstring. Note that the default
 is 'valid', unlike `convolve`, which uses 'full'.
 propagate_mask : bool
 If True, then a result element is masked if any masked element contributes
 towards it. If False, then a result element is only masked if no non-masked
 element contribute towards it
 Returns
 -------
 out : MaskedArray
 Discrete cross-correlation of `a` and `v`.
 See Also
 --------
 numpy.correlate : Equivalent function in the top-level NumPy module.
 Examples
 --------
 Basic correlation:
 >>> a = np.ma.array([1, 2, 3])
 >>> v = np.ma.array([0, 1, 0])
 >>> np.ma.correlate(a, v, mode='valid')
 masked_array(data=[2],
 mask=[False],
 fill_value=999999)
 Correlation with masked elements:
 >>> a = np.ma.array([1, 2, 3], mask=[False, True, False])
 >>> v = np.ma.array([0, 1, 0])
 >>> np.ma.correlate(a, v, mode='valid', propagate_mask=True)
 masked_array(data=[--],
 mask=[ True],
 fill_value=999999,
 dtype=int64)
 Correlation with different modes and mixed array types:
 >>> a = np.ma.array([1, 2, 3])
 >>> v = np.ma.array([0, 1, 0])
 >>> np.ma.correlate(a, v, mode='full')
 masked_array(data=[0, 1, 2, 3, 0],
 mask=[False, False, False, False, False],
 fill_value=999999)
 """
 return _convolve_or_correlate(np.correlate, a, v, mode, propagate_mask)
def convolve(a, v, mode='full', propagate_mask=True):
 """
 Returns the discrete, linear convolution of two one-dimensional sequences.
 Parameters
 ----------
 a, v : array_like
 Input sequences.
 mode : {'valid', 'same', 'full'}, optional
 Refer to the `np.convolve` docstring.
 propagate_mask : bool
 If True, then if any masked element is included in the sum for a result
 element, then the result is masked.
 If False, then the result element is only masked if no non-masked cells
 contribute towards it
 Returns
 -------
 out : MaskedArray
 Discrete, linear convolution of `a` and `v`.
 See Also
 --------
 numpy.convolve : Equivalent function in the top-level NumPy module.
 """
 return _convolve_or_correlate(np.convolve, a, v, mode, propagate_mask)
def allequal(a, b, fill_value=True):
 """
 Return True if all entries of a and b are equal, using
 fill_value as a truth value where either or both are masked.
 Parameters
 ----------
 a, b : array_like
 Input arrays to compare.
 fill_value : bool, optional
 Whether masked values in a or b are considered equal (True) or not
 (False).
 Returns
 -------
 y : bool
 Returns True if the two arrays are equal within the given
 tolerance, False otherwise. If either array contains NaN,
 then False is returned.
 See Also
 --------
 all, any
 numpy.ma.allclose
 Examples
 --------
 >>> import numpy as np
 >>> a = np.ma.array([1e10, 1e-7, 42.0], mask=[0, 0, 1])
 >>> a
 masked_array(data=[10000000000.0, 1e-07, --],
 mask=[False, False, True],
 fill_value=1e+20)
 >>> b = np.array([1e10, 1e-7, -42.0])
 >>> b
 array([ 1.00000000e+10, 1.00000000e-07, -4.20000000e+01])
 >>> np.ma.allequal(a, b, fill_value=False)
 False
 >>> np.ma.allequal(a, b)
 True
 """
 m = mask_or(getmask(a), getmask(b))
 if m is nomask:
 x = getdata(a)
 y = getdata(b)
 d = umath.equal(x, y)
 return d.all()
 elif fill_value:
 x = getdata(a)
 y = getdata(b)
 d = umath.equal(x, y)
 dm = array(d, mask=m, copy=False)
 return dm.filled(True).all(None)
 else:
 return False
def allclose(a, b, masked_equal=True, rtol=1e-5, atol=1e-8):
 """
 Returns True if two arrays are element-wise equal within a tolerance.
 This function is equivalent to `allclose` except that masked values
 are treated as equal (default) or unequal, depending on the `masked_equal`
 argument.
 Parameters
 ----------
 a, b : array_like
 Input arrays to compare.
 masked_equal : bool, optional
 Whether masked values in `a` and `b` are considered equal (True) or not
 (False). They are considered equal by default.
 rtol : float, optional
 Relative tolerance. The relative difference is equal to ``rtol * b``.
 Default is 1e-5.
 atol : float, optional
 Absolute tolerance. The absolute difference is equal to `atol`.
 Default is 1e-8.
 Returns
 -------
 y : bool
 Returns True if the two arrays are equal within the given
 tolerance, False otherwise. If either array contains NaN, then
 False is returned.
 See Also
 --------
 all, any
 numpy.allclose : the non-masked `allclose`.
 Notes
 -----
 If the following equation is element-wise True, then `allclose` returns
 True::
 absolute(`a` - `b`) <= (`atol` + `rtol` * absolute(`b`))
 Return True if all elements of `a` and `b` are equal subject to
 given tolerances.
 Examples
 --------
 >>> import numpy as np
 >>> a = np.ma.array([1e10, 1e-7, 42.0], mask=[0, 0, 1])
 >>> a
 masked_array(data=[10000000000.0, 1e-07, --],
 mask=[False, False, True],
 fill_value=1e+20)
 >>> b = np.ma.array([1e10, 1e-8, -42.0], mask=[0, 0, 1])
 >>> np.ma.allclose(a, b)
 False
 >>> a = np.ma.array([1e10, 1e-8, 42.0], mask=[0, 0, 1])
 >>> b = np.ma.array([1.00001e10, 1e-9, -42.0], mask=[0, 0, 1])
 >>> np.ma.allclose(a, b)
 True
 >>> np.ma.allclose(a, b, masked_equal=False)
 False
 Masked values are not compared directly.
 >>> a = np.ma.array([1e10, 1e-8, 42.0], mask=[0, 0, 1])
 >>> b = np.ma.array([1.00001e10, 1e-9, 42.0], mask=[0, 0, 1])
 >>> np.ma.allclose(a, b)
 True
 >>> np.ma.allclose(a, b, masked_equal=False)
 False
 """
 x = masked_array(a, copy=False)
 y = masked_array(b, copy=False)
# make sure y is an inexact type to avoid abs(MIN_INT); will cause
 # casting of x later.
 # NOTE: We explicitly allow timedelta, which used to work. This could
 # possibly be deprecated. See also gh-18286.
 # timedelta works if `atol` is an integer or also a timedelta.
 # Although, the default tolerances are unlikely to be useful
 if y.dtype.kind != "m":
 dtype = np.result_type(y, 1.)
 if y.dtype != dtype:
 y = masked_array(y, dtype=dtype, copy=False)
m = mask_or(getmask(x), getmask(y))
 xinf = np.isinf(masked_array(x, copy=False, mask=m)).filled(False)
 # If we have some infs, they should fall at the same place.
 if not np.all(xinf == filled(np.isinf(y), False)):
 return False
 # No infs at all
 if not np.any(xinf):
 d = filled(less_equal(absolute(x - y), atol + rtol * absolute(y)),
 masked_equal)
 return np.all(d)
if not np.all(filled(x[xinf] == y[xinf], masked_equal)):
 return False
 x = x[~xinf]
 y = y[~xinf]
d = filled(less_equal(absolute(x - y), atol + rtol * absolute(y)),
 masked_equal)
return np.all(d)
def asarray(a, dtype=None, order=None):
 """
 Convert the input to a masked array of the given data-type.
 No copy is performed if the input is already an `ndarray`. If `a` is
 a subclass of `MaskedArray`, a base class `MaskedArray` is returned.
 Parameters
 ----------
 a : array_like
 Input data, in any form that can be converted to a masked array. This
 includes lists, lists of tuples, tuples, tuples of tuples, tuples
 of lists, ndarrays and masked arrays.
 dtype : dtype, optional
 By default, the data-type is inferred from the input data.
 order : {'C', 'F'}, optional
 Whether to use row-major ('C') or column-major ('FORTRAN') memory
 representation. Default is 'C'.
 Returns
 -------
 out : MaskedArray
 Masked array interpretation of `a`.
 See Also
 --------
 asanyarray : Similar to `asarray`, but conserves subclasses.
 Examples
 --------
 >>> import numpy as np
 >>> x = np.arange(10.).reshape(2, 5)
 >>> x
 array([[0., 1., 2., 3., 4.],
 [5., 6., 7., 8., 9.]])
 >>> np.ma.asarray(x)
 masked_array(
 data=[[0., 1., 2., 3., 4.],
 [5., 6., 7., 8., 9.]],
 mask=False,
 fill_value=1e+20)
 >>> type(np.ma.asarray(x))
 <class 'numpy.ma.MaskedArray'>
 """
 order = order or 'C'
 return masked_array(a, dtype=dtype, copy=False, keep_mask=True,
 subok=False, order=order)
def asanyarray(a, dtype=None, order=None):
 """
 Convert the input to a masked array, conserving subclasses.
 If `a` is a subclass of `MaskedArray`, its class is conserved.
 No copy is performed if the input is already an `ndarray`.
 Parameters
 ----------
 a : array_like
 Input data, in any form that can be converted to an array.
 dtype : dtype, optional
 By default, the data-type is inferred from the input data.
 order : {'C', 'F', 'A', 'K'}, optional
 Memory layout. 'A' and 'K' depend on the order of input array ``a``.
 'C' row-major (C-style),
 'F' column-major (Fortran-style) memory representation.
 'A' (any) means 'F' if ``a`` is Fortran contiguous, 'C' otherwise
 'K' (keep) preserve input order
 Defaults to 'K'.
 Returns
 -------
 out : MaskedArray
 MaskedArray interpretation of `a`.
 See Also
 --------
 asarray : Similar to `asanyarray`, but does not conserve subclass.
 Examples
 --------
 >>> import numpy as np
 >>> x = np.arange(10.).reshape(2, 5)
 >>> x
 array([[0., 1., 2., 3., 4.],
 [5., 6., 7., 8., 9.]])
 >>> np.ma.asanyarray(x)
 masked_array(
 data=[[0., 1., 2., 3., 4.],
 [5., 6., 7., 8., 9.]],
 mask=False,
 fill_value=1e+20)
 >>> type(np.ma.asanyarray(x))
 <class 'numpy.ma.MaskedArray'>
 """
 # workaround for #8666, to preserve identity. Ideally the bottom line
 # would handle this for us.
 if (
 isinstance(a, MaskedArray)
 and (dtype is None or dtype == a.dtype)
 and (
 order in {None, 'A', 'K'}
 or order == 'C' and a.flags.carray
 or order == 'F' and a.flags.f_contiguous
 )
 ):
 return a
 return masked_array(a, dtype=dtype, copy=False, keep_mask=True, subok=True,
 order=order)
##############################################################################
# Pickling #
##############################################################################
def fromfile(file, dtype=float, count=-1, sep=''):
 raise NotImplementedError(
 "fromfile() not yet implemented for a MaskedArray.")
def fromflex(fxarray):
 """
 Build a masked array from a suitable flexible-type array.
 The input array has to have a data-type with ``_data`` and ``_mask``
 fields. This type of array is output by `MaskedArray.toflex`.
 Parameters
 ----------
 fxarray : ndarray
 The structured input array, containing ``_data`` and ``_mask``
 fields. If present, other fields are discarded.
 Returns
 -------
 result : MaskedArray
 The constructed masked array.
 See Also
 --------
 MaskedArray.toflex : Build a flexible-type array from a masked array.
 Examples
 --------
 >>> import numpy as np
 >>> x = np.ma.array(np.arange(9).reshape(3, 3), mask=[0] + [1, 0] * 4)
 >>> rec = x.toflex()
 >>> rec
 array([[(0, False), (1, True), (2, False)],
 [(3, True), (4, False), (5, True)],
 [(6, False), (7, True), (8, False)]],
 dtype=[('_data', '<i8'), ('_mask', '?')])
 >>> x2 = np.ma.fromflex(rec)
 >>> x2
 masked_array(
 data=[[0, --, 2],
 [--, 4, --],
 [6, --, 8]],
 mask=[[False, True, False],
 [ True, False, True],
 [False, True, False]],
 fill_value=999999)
 Extra fields can be present in the structured array but are discarded:
 >>> dt = [('_data', '<i4'), ('_mask', '|b1'), ('field3', '<f4')]
 >>> rec2 = np.zeros((2, 2), dtype=dt)
 >>> rec2
 array([[(0, False, 0.), (0, False, 0.)],
 [(0, False, 0.), (0, False, 0.)]],
 dtype=[('_data', '<i4'), ('_mask', '?'), ('field3', '<f4')])
 >>> y = np.ma.fromflex(rec2)
 >>> y
 masked_array(
 data=[[0, 0],
 [0, 0]],
 mask=[[False, False],
 [False, False]],
 fill_value=np.int64(999999),
 dtype=int32)
 """
 return masked_array(fxarray['_data'], mask=fxarray['_mask'])
def _convert2ma(funcname: str, np_ret: str, np_ma_ret: str,
 params: dict[str, str] | None = None):
 """Convert function from numpy to numpy.ma."""
 func = getattr(np, funcname)
 params = params or {}
@functools.wraps(func, assigned=set(functools.WRAPPER_ASSIGNMENTS) - {"__module__"})
 def wrapper(*args, **kwargs):
 common_params = kwargs.keys() & params.keys()
 extras = params | {p: kwargs.pop(p) for p in common_params}
result = func.__call__(*args, **kwargs).view(MaskedArray)
if "fill_value" in common_params:
 result.fill_value = extras["fill_value"]
 if "hardmask" in common_params:
 result._hardmask = bool(extras["hardmask"])
return result
# workaround for a doctest bug in Python 3.11 that incorrectly assumes `__code__`
 # exists on wrapped functions
 del wrapper.__wrapped__
# `arange`, `empty`, `empty_like`, `frombuffer`, and `zeros` have no signature
 try:
 signature = inspect.signature(func)
 except ValueError:
 signature = inspect.Signature([
 inspect.Parameter('args', inspect.Parameter.VAR_POSITIONAL),
 inspect.Parameter('kwargs', inspect.Parameter.VAR_KEYWORD),
 ])
if params:
 sig_params = list(signature.parameters.values())
# pop `**kwargs` if present
 sig_kwargs = None
 if sig_params[-1].kind is inspect.Parameter.VAR_KEYWORD:
 sig_kwargs = sig_params.pop()
# add new keyword-only parameters
 for param_name, default in params.items():
 new_param = inspect.Parameter(
 param_name,
 inspect.Parameter.KEYWORD_ONLY,
 default=default,
 )
 sig_params.append(new_param)
# re-append `**kwargs` if it was present
 if sig_kwargs:
 sig_params.append(sig_kwargs)
signature = signature.replace(parameters=sig_params)
wrapper.__signature__ = signature
# __doc__ is None when using `python -OO ...`
 if func.__doc__ is not None:
 assert np_ret in func.__doc__, (
 f"Failed to replace `{np_ret}` with `{np_ma_ret}`. "
 f"The documentation string for return type, {np_ret}, is not "
 f"found in the docstring for `np.{func.__name__}`. "
 f"Fix the docstring for `np.{func.__name__}` or "
 "update the expected string for return type."
 )
 wrapper.__doc__ = inspect.cleandoc(func.__doc__).replace(np_ret, np_ma_ret)
return wrapper
arange = _convert2ma(
 'arange',
 params={'fill_value': None, 'hardmask': False},
 np_ret='arange : ndarray',
 np_ma_ret='arange : MaskedArray',
)
clip = _convert2ma(
 'clip',
 params={'fill_value': None, 'hardmask': False},
 np_ret='clipped_array : ndarray',
 np_ma_ret='clipped_array : MaskedArray',
)
empty = _convert2ma(
 'empty',
 params={'fill_value': None, 'hardmask': False},
 np_ret='out : ndarray',
 np_ma_ret='out : MaskedArray',
)
empty_like = _convert2ma(
 'empty_like',
 np_ret='out : ndarray',
 np_ma_ret='out : MaskedArray',
)
frombuffer = _convert2ma(
 'frombuffer',
 np_ret='out : ndarray',
 np_ma_ret='out: MaskedArray',
)
fromfunction = _convert2ma(
 'fromfunction',
 np_ret='fromfunction : any',
 np_ma_ret='fromfunction: MaskedArray',
)
identity = _convert2ma(
 'identity',
 params={'fill_value': None, 'hardmask': False},
 np_ret='out : ndarray',
 np_ma_ret='out : MaskedArray',
)
indices = _convert2ma(
 'indices',
 params={'fill_value': None, 'hardmask': False},
 np_ret='grid : one ndarray or tuple of ndarrays',
 np_ma_ret='grid : one MaskedArray or tuple of MaskedArrays',
)
ones = _convert2ma(
 'ones',
 params={'fill_value': None, 'hardmask': False},
 np_ret='out : ndarray',
 np_ma_ret='out : MaskedArray',
)
ones_like = _convert2ma(
 'ones_like',
 np_ret='out : ndarray',
 np_ma_ret='out : MaskedArray',
)
squeeze = _convert2ma(
 'squeeze',
 params={'fill_value': None, 'hardmask': False},
 np_ret='squeezed : ndarray',
 np_ma_ret='squeezed : MaskedArray',
)
zeros = _convert2ma(
 'zeros',
 params={'fill_value': None, 'hardmask': False},
 np_ret='out : ndarray',
 np_ma_ret='out : MaskedArray',
)
zeros_like = _convert2ma(
 'zeros_like',
 np_ret='out : ndarray',
 np_ma_ret='out : MaskedArray',
)
def append(a, b, axis=None):
 """Append values to the end of an array.
 Parameters
 ----------
 a : array_like
 Values are appended to a copy of this array.
 b : array_like
 These values are appended to a copy of `a`. It must be of the
 correct shape (the same shape as `a`, excluding `axis`). If `axis`
 is not specified, `b` can be any shape and will be flattened
 before use.
 axis : int, optional
 The axis along which `v` are appended. If `axis` is not given,
 both `a` and `b` are flattened before use.
 Returns
 -------
 append : MaskedArray
 A copy of `a` with `b` appended to `axis`. Note that `append`
 does not occur in-place: a new array is allocated and filled. If
 `axis` is None, the result is a flattened array.
 See Also
 --------
 numpy.append : Equivalent function in the top-level NumPy module.
 Examples
 --------
 >>> import numpy as np
 >>> import numpy.ma as ma
 >>> a = ma.masked_values([1, 2, 3], 2)
 >>> b = ma.masked_values([[4, 5, 6], [7, 8, 9]], 7)
 >>> ma.append(a, b)
 masked_array(data=[1, --, 3, 4, 5, 6, --, 8, 9],
 mask=[False, True, False, False, False, False, True, False,
 False],
 fill_value=999999)
 """
 return concatenate([a, b], axis)

Xet Storage Details

Size:
289 kB
·
Xet hash:
5fe7391608c9f2399d0143f0abe2e03210cac139b4233eabcb27163e238a83c4

Xet efficiently stores files, intelligently splitting them into unique chunks and accelerating uploads and downloads. More info.