Sha256: 4ab627f8ff5ea244bfac8d5603be57b4bf7ab31437c403bcae8b11756bdee335
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Size: 981 Bytes
Versions: 6
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Stored size: 981 Bytes
Contents
module Enumerable
unless method_defined?(:one?) # 1.8.7+
# Enumerable#one? returns +true+ if and only if <em>exactly one</em>
# element in the collection satisfies the given predicate.
#
# If no predicate is provided, Enumerable#one? returns +true+ if
# and only if <em>exactly one</em> element has a true value
# (i.e. not +nil+ or +false+).
#
# [].one? # false
# [nil].one? # false
# [5].one? # true
# [5,8,9].one? # false
# (1...10).one? { |n| n == 5 } # true
# (1...10).one? { |n| n < 5 } # false
#
# CREDIT: Gavin Sinclair
def one? # :yield: e
matches = 0
if block_given?
self.each do |e|
if yield(e)
matches += 1
return false if matches > 1
end
end
return (matches == 1)
else
one? { |e| e }
end
end
end
end
Version data entries
6 entries across 6 versions & 1 rubygems