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gadams
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ruby

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first, second = multi_return
# good - use with splat
first, *list = [1, 2, 3, 4] # first => 1, list => [2, 3, 4]
hello_array = *'Hello' # => ["Hello"]
a = *(1..3) # => [1, 2, 3]
----
=== Values Swapping [[values-swapping]]
Use parallel assignment when swapping 2 values.
[source,ruby]
----
# bad
tmp = x
x = y
y = tmp
# good
x, y = y, x
----
=== Dealing with Trailing Underscore Variables in Destructuring Assignment [[trailing-underscore-variables]]
Avoid the use of unnecessary trailing underscore variables during
parallel assignment. Named underscore variables are to be preferred over
underscore variables because of the context that they provide.
Trailing underscore variables are necessary when there is a splat variable
defined on the left side of the assignment, and the splat variable is
not an underscore.
[source,ruby]
----
# bad
foo = 'one,two,three,four,five'
# Unnecessary assignment that does not provide useful information
first, second, _ = foo.split(',')
first, _, _ = foo.split(',')
first, *_ = foo.split(',')
# good
foo = 'one,two,three,four,five'
# The underscores are needed to show that you want all elements
# except for the last number of underscore elements
*beginning, _ = foo.split(',')
*beginning, something, _ = foo.split(',')
a, = foo.split(',')
a, b, = foo.split(',')
# Unnecessary assignment to an unused variable, but the assignment
# provides us with useful information.
first, _second = foo.split(',')
first, _second, = foo.split(',')
first, *_ending = foo.split(',')
----
=== Self-assignment [[self-assignment]]
Use shorthand self assignment operators whenever applicable.
[source,ruby]
----
# bad
x = x + y
x = x * y
x = x**y
x = x / y
x = x || y
x = x && y
# good
x += y
x *= y
x **= y
x /= y
x ||= y
x &&= y
----
=== Conditional Variable Initialization Shorthand [[double-pipe-for-uninit]]
Use `||=` to initialize variables only if they're not already initialized.
[source,ruby]
----
# bad
name = name ? name : 'Bozhidar'
# bad
name = 'Bozhidar' unless name
# good - set name to 'Bozhidar', only if it's nil or false
name ||= 'Bozhidar'
----
[WARNING]