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| """Bio.SeqIO support for the "phd" file format. |
| |
| PHD files are output by PHRED and used by PHRAP and CONSED. |
| |
| You are expected to use this module via the Bio.SeqIO functions, under the |
| format name "phd". See also the underlying Bio.Sequencing.Phd module. |
| |
| For example, using Bio.SeqIO we can read in one of the example PHRED files |
| from the Biopython unit tests: |
| |
| >>> from Bio import SeqIO |
| >>> for record in SeqIO.parse("Phd/phd1", "phd"): |
| ... print(record.id) |
| ... print("%s..." % record.seq[:10]) |
| ... print("%s..." % record.letter_annotations["phred_quality"][:10]) |
| 34_222_(80-A03-19).b.ab1 |
| ctccgtcgga... |
| [9, 9, 10, 19, 22, 37, 28, 28, 24, 22]... |
| 425_103_(81-A03-19).g.ab1 |
| cgggatccca... |
| [14, 17, 22, 10, 10, 10, 15, 8, 8, 9]... |
| 425_7_(71-A03-19).b.ab1 |
| acataaatca... |
| [10, 10, 10, 10, 8, 8, 6, 6, 6, 6]... |
| |
| Since PHRED files contain quality scores, you can save them as FASTQ or as |
| QUAL files, for example using Bio.SeqIO.write(...), or simply with the format |
| method of the SeqRecord object: |
| |
| >>> print(record[:50].format("fastq")) |
| @425_7_(71-A03-19).b.ab1 |
| acataaatcaaattactnaccaacacacaaaccngtctcgcgtagtggag |
| + |
| ++++))'''')(''')$!$''')''''(+.''$!$))))+)))''''''' |
| <BLANKLINE> |
| |
| Or, |
| |
| >>> print(record[:50].format("qual")) |
| >425_7_(71-A03-19).b.ab1 |
| 10 10 10 10 8 8 6 6 6 6 8 7 6 6 6 8 3 0 3 6 6 6 8 6 6 6 6 7 |
| 10 13 6 6 3 0 3 8 8 8 8 10 8 8 8 6 6 6 6 6 6 6 |
| <BLANKLINE> |
| |
| Note these examples only show the first 50 bases to keep the output short. |
| """ |
|
|
| from collections.abc import Iterator |
|
|
| from Bio.SeqRecord import SeqRecord |
| from Bio.Sequencing import Phd |
|
|
| from .Interfaces import _IOSource |
| from .Interfaces import _TextIOSource |
| from .Interfaces import SequenceIterator |
| from .Interfaces import SequenceWriter |
| from .QualityIO import _get_phred_quality |
|
|
|
|
| class PhdIterator(SequenceIterator): |
| """Parser for PHD files.""" |
|
|
| modes = "t" |
|
|
| def __init__(self, source: _TextIOSource) -> None: |
| """Return SeqRecord objects from a PHD file. |
| |
| Arguments: |
| - source - input stream opened in text mode, or a path to a file |
| |
| This uses the Bio.Sequencing.Phd module to do the hard work. |
| """ |
| super().__init__(source, fmt="PHD") |
|
|
| def __next__(self): |
| phd_record = Phd._read(self.stream) |
| if phd_record is None: |
| raise StopIteration |
| |
| |
| |
| |
| |
| name = phd_record.file_name.split(None, 1)[0] |
| seq_record = SeqRecord( |
| phd_record.seq, id=name, name=name, description=phd_record.file_name |
| ) |
| |
| seq_record.annotations = phd_record.comments |
| seq_record.annotations["molecule_type"] = "DNA" |
| |
| seq_record.letter_annotations["phred_quality"] = [ |
| int(site[1]) for site in phd_record.sites |
| ] |
| try: |
| seq_record.letter_annotations["peak_location"] = [ |
| int(site[2]) for site in phd_record.sites |
| ] |
| except IndexError: |
| |
| |
| pass |
| return seq_record |
|
|
|
|
| class PhdWriter(SequenceWriter): |
| """Class to write Phd format files.""" |
|
|
| modes = "t" |
|
|
| def write_record(self, record): |
| """Write a single Phd record to the file.""" |
| assert record.seq, "No sequence present in SeqRecord" |
| |
| |
| phred_qualities = _get_phred_quality(record) |
| peak_locations = record.letter_annotations.get("peak_location") |
| if len(record.seq) != len(phred_qualities): |
| raise ValueError( |
| "Number of phd quality scores does not match length of sequence" |
| ) |
| if peak_locations: |
| if len(record.seq) != len(peak_locations): |
| raise ValueError( |
| "Number of peak location scores does not match length of sequence" |
| ) |
| if None in phred_qualities: |
| raise ValueError("A quality value of None was found") |
| if record.description.startswith(f"{record.id} "): |
| title = record.description |
| else: |
| title = f"{record.id} {record.description}" |
| self.handle.write(f"BEGIN_SEQUENCE {self.clean(title)}\nBEGIN_COMMENT\n") |
| for annot in [k.lower() for k in Phd.CKEYWORDS]: |
| value = None |
| if annot == "trim": |
| if record.annotations.get("trim"): |
| value = "%s %s %.4f" % record.annotations["trim"] |
| elif annot == "trace_peak_area_ratio": |
| if record.annotations.get("trace_peak_area_ratio"): |
| value = f"{record.annotations['trace_peak_area_ratio']:.4f}" |
| else: |
| value = record.annotations.get(annot) |
| if value or value == 0: |
| self.handle.write(f"{annot.upper()}: {value}\n") |
|
|
| self.handle.write("END_COMMENT\nBEGIN_DNA\n") |
| for i, site in enumerate(record.seq): |
| if peak_locations: |
| self.handle.write( |
| "%s %i %i\n" % (site, round(phred_qualities[i]), peak_locations[i]) |
| ) |
| else: |
| self.handle.write("%s %i\n" % (site, round(phred_qualities[i]))) |
|
|
| self.handle.write("END_DNA\nEND_SEQUENCE\n") |
|
|
|
|
| if __name__ == "__main__": |
| from Bio._utils import run_doctest |
|
|
| run_doctest() |
|
|