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Versions: 5
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Contents
unless (RUBY_VERSION[0,3] == '1.9')
class Array
# Provides the cross-product of two or more Enumerables.
# This is the class-level method. The instance method
# calls on this.
#
# Enumerable.cartesian_product([1,2], [4], ["apple", "banana"])
# #=> [[1, 4, "apple"], [1, 4, "banana"], [2, 4, "apple"], [2, 4, "banana"]]
#
# Enumerable.cartesian_product([1,2], [3,4])
# #=> [[1, 3], [1, 4], [2, 3], [2, 4]]
#
# a = []
# [1,2].cart([4,5]){|elem| a << elem }
# a #=> [[1, 4],[1, 5],[2, 4],[2, 5]]
#
# CREDIT: Thomas Hafner
def product(*enums, &block)
enums.unshift self
result = [[]]
while [] != enums
t, result = result, []
b, *enums = enums
t.each do |a|
b.each do |n|
result << a + [n]
end
end
end
if block_given?
result.each{ |e| block.call(e) }
else
result
end
end
end
end
class Array
# Operator alias for cross-product.
#
# a = [1,2] ** [4,5]
# a #=> [[1, 4],[1, 5],[2, 4],[2, 5]]
#
# CREDIT: Trans
alias_method :**, :product
end
Version data entries
5 entries across 5 versions & 2 rubygems