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##
# Enumerable
#
module Enumerable
##
# call-seq:
# enum.drop(n) -> array
#
# Drops first n elements from <i>enum</i>, and returns rest elements
# in an array.
#
# a = [1, 2, 3, 4, 5, 0]
# a.drop(3) #=> [4, 5, 0]
def drop(n)
raise TypeError, "expected Integer for 1st argument" unless n.kind_of? Integer
raise ArgumentError, "attempt to drop negative size" if n < 0
ary = []
self.each {|e| n == 0 ? ary << e : n -= 1 }
ary
end
##
# call-seq:
# enum.drop_while {|arr| block } -> array
#
# Drops elements up to, but not including, the first element for
# which the block returns +nil+ or +false+ and returns an array
# containing the remaining elements.
#
# a = [1, 2, 3, 4, 5, 0]
# a.drop_while {|i| i < 3 } #=> [3, 4, 5, 0]
def drop_while(&block)
ary, state = [], false
self.each do |e|
state = true if !state and !block.call(e)
ary << e if state
end
ary
end
##
# call-seq:
# enum.take(n) -> array
#
# Returns first n elements from <i>enum</i>.
#
# a = [1, 2, 3, 4, 5, 0]
# a.take(3) #=> [1, 2, 3]
def take(n)
raise TypeError, "expected Integer for 1st argument" unless n.kind_of? Integer
raise ArgumentError, "attempt to take negative size" if n < 0
ary = []
self.each do |e|
break if ary.size >= n
ary << e
end
ary
end
##
# call-seq:
# enum.take_while {|arr| block } -> array
#
# Passes elements to the block until the block returns +nil+ or +false+,
# then stops iterating and returns an array of all prior elements.
#
#
# a = [1, 2, 3, 4, 5, 0]
# a.take_while {|i| i < 3 } #=> [1, 2]
def take_while(&block)
ary = []
self.each do |e|
return ary unless block.call(e)
ary << e
end
ary
end
##
# call-seq:
# enum.each_cons(n) {...} -> nil
#
# Iterates the given block for each array of consecutive <n>
# elements.
#
# e.g.:
# (1..10).each_cons(3) {|a| p a}
# # outputs below
# [1, 2, 3]
# [2, 3, 4]
# [3, 4, 5]
# [4, 5, 6]
# [5, 6, 7]
# [6, 7, 8]
# [7, 8, 9]
# [8, 9, 10]
def each_cons(n, &block)
raise TypeError, "expected Integer for 1st argument" unless n.kind_of? Integer
raise ArgumentError, "invalid size" if n <= 0
ary = []
self.each do |e|
ary.shift if ary.size == n
ary << e
block.call(ary.dup) if ary.size == n
end
end
##
# call-seq:
# enum.each_slice(n) {...} -> nil
#
# Iterates the given block for each slice of <n> elements.
#
# e.g.:
# (1..10).each_slice(3) {|a| p a}
# # outputs below
# [1, 2, 3]
# [4, 5, 6]
# [7, 8, 9]
# [10]
def each_slice(n, &block)
raise TypeError, "expected Integer for 1st argument" unless n.kind_of? Integer
raise ArgumentError, "invalid slice size" if n <= 0
ary = []
self.each do |e|
ary << e
if ary.size == n
block.call(ary)
ary = []
end
end
block.call(ary) unless ary.empty?
end
end
|
