Sha256: 160bd7873f0d88059d0560a48a121f4df75e4c8637fdf642f3aa7bdf36362ca7
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Size: 965 Bytes
Versions: 4
Compression:
Stored size: 965 Bytes
Contents
class Array
# Similar to +reduce+/+inject+, but also returns intermediate values. Has the
# same interface as +reduce+/+inject+, so an initial value, an operator or
# both can be supplied. This method may eventually be moved to the
# +Enumerable+ module.
#
# @example Symbol argument
# a = (1..4).to_a
# a.reductions(:+) #=> 10
# @example Initial value and symbol argument
# a.reductions(50, :+) #=> 60
# @example Block argument
# %w(a b c).reductions { |s1, s2| s1+s2 } #=> ["a", "ab", "abc"]
def reductions(*args, &block)
arr = dup
if args.size == 1
Symbol === (arg = args.first) ? op = arg : initial = arg
else
initial, op, _ = args
end
raise ArgumentError, "Need an operator or block" unless op || block
initial ||= arr.shift
arr.inject([initial, [initial]]) { |(acc, result), el|
val = op ? acc.send(op, el) : yield(acc, el)
[val, result << val]
}.last
end
end
Version data entries
4 entries across 4 versions & 1 rubygems