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Contents
module Enumerable
# Returns an array of elements for the elements that occur n times.
# Or according to the results of a given block.
#
# [1,1,2,3,3,4,5,5].occur(1) #=> [2,4]
# [1,1,2,3,3,4,5,5].occur(2) #=> [1,3,5]
# [1,1,2,3,3,4,5,5].occur(3) #=> []
#
# [1,2,2,3,3,3].occur(1..1) #=> [1]
# [1,2,2,3,3,3].occur(2..3) #=> [2,3]
#
# [1,1,2,3,3,4,5,5].occur { |n| n == 1 } #=> [2,4]
# [1,1,2,3,3,4,5,5].occur { |n| n > 1 } #=> [1,3,5]
#
def occur(n=nil) #:yield:
result = Hash.new { |hash, key| hash[key] = Array.new }
self.each do |item|
key = item
result[key] << item
end
if block_given?
result.reject! { |key, values| ! yield(values.size) }
else
raise ArgumentError unless n
if Range === n
result.reject! { |key, values| ! n.include?(values.size) }
else
result.reject! { |key, values| values.size != n }
end
end
return result.values.flatten.uniq
end
end
# _____ _
# |_ _|__ ___| |_
# | |/ _ \/ __| __|
# | | __/\__ \ |_
# |_|\___||___/\__|
#
=begin test
require 'test/unit'
class TCEnumerable < Test::Unit::TestCase
def test_occur
arr = [:a,:b,:a]
assert_equal( [:b], arr.occur(1) )
assert_equal( [:a], arr.occur(2) )
assert_equal( [:b], arr.occur(1..1) )
assert_equal( [:a], arr.occur{ |n| n % 2 == 0 } )
end
end
=end
Version data entries
26 entries across 26 versions & 1 rubygems