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Feature #10726 » implement_set_powerset.patch

gogotanaka (Kazuki Tanaka), 01/27/2015 05:48 PM

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NEWS
=== Stdlib updates (outstanding ones only)
* lib/set.rb
* New methods:
* Set#powerset returns set of all subsets of +self+.
=== Stdlib compatibility issues (excluding feature bug fixes)
* lib/webrick/utils.rb
lib/set.rb
end
end
# Returns set of all subsets of +self+.
#
# e.g.:
#
# require 'set'
# set = Set[1, 2].powerset
# p set # => #<Set: {#<Set: {}>,
# # #<Set: {1}>,
# # #<Set: {2}>,
# # #<Set: {1, 2}>}>
def powerset
(0 .. 2 ** length - 1).map { |n|
select.with_index { |_, i| (n >> i) & 1 == 1 }.to_set
}.to_set
end
InspectKey = :__inspect_key__ # :nodoc:
# Returns a string containing a human-readable representation of the
test/test_set.rb
}
end
def test_powerset
assert_equal(Set[1, 2].powerset, Set[Set[], Set[1], Set[2], Set[1, 2]])
assert_equal(
Set[1, 2, 3].powerset,
Set[Set[], Set[1], Set[2], Set[3], Set[1, 2], Set[2, 3], Set[3, 1], Set[1, 2, 3]]
)
end
def test_taintness
orig = set = Set[1,2,3]
assert_equal false, set.tainted?
-
(5-5/5)