Issue #8707 has been updated by bughit (bug hit). Another point is that that hash.reverse_each already exists via enumerable, but with a highly suboptimal array conversion. If it didn't exist you could perhaps debate whether it should be added, but that's moot at this point. The only question here is whether hash.reverse_each should be a hidden perf land-mine or have an optimal implementation for a Hash. Seems like a no-brainer. ---------------------------------------- Feature #8707: Hash#reverse_each https://bugs.ruby-lang.org/issues/8707#change-102948 * Author: Glass_saga (Masaki Matsushita) * Status: Feedback * Priority: Normal * Assignee: matz (Yukihiro Matsumoto) ---------------------------------------- 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) ---Files-------------------------------- patch.diff (7.55 KB) -- https://bugs.ruby-lang.org/