Feature #8707
openHash#reverse_each
Description
Currently, {}.reverse_each calls Enumerable#reverse_each.
It will make array and its size can be large.
I made Hash#reverse_each to avoid array creation and performance improvement.
benchmark:
require "benchmark"
Size = 10000
HASH = Hash[*Array.new(Size) {|i| [i, true] }.flatten]
Benchmark.bmbm do |x|
x.report("Hash#reverse_each") do
300.times do
HASH.reverse_each {|a, b|}
end
end
end
result:
trunk(r42256):
Rehearsal -----------------------------------------------------
Hash#reverse_each 1.210000 0.000000 1.210000 ( 1.207964)
-------------------------------------------- total: 1.210000sec
user system total real
Hash#reverse_each 0.950000 0.000000 0.950000 ( 0.951069)
proposal:
Rehearsal -----------------------------------------------------
Hash#reverse_each 0.600000 0.000000 0.600000 ( 0.600242)
-------------------------------------------- total: 0.600000sec
user system total real
Hash#reverse_each 0.450000 0.000000 0.450000 ( 0.459006)
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