From: "trans (Thomas Sawyer)" Date: 2012-08-07T15:11:03+09:00 Subject: [ruby-core:47046] [ruby-trunk - Bug #6596] New method for Arrays : Array#index Issue #6596 has been updated by trans (Thomas Sawyer). Given a ordered list, swap items relative to those that match. list.index_all{ |x| match?(x) }.each do |i| list[i], list[i+1] = list[i+1], list[i] end vs. what? list.each_with_index do |x, i| if match?(x) list[i], list[i+1] = list[i+1], list[i] end end Nope, that doesn't work. Could clone `list` but that would be rather inefficient. Better idea? A built-in #index_all is going to be a lot faster then a Ruby code implementation of the same. ---------------------------------------- Bug #6596: New method for Arrays : Array#index https://bugs.ruby-lang.org/issues/6596#change-28701 Author: robin850 (Robin Dupret) Status: Feedback Priority: Normal Assignee: Category: core Target version: 2.0.0 ruby -v: 2.0.0 Hello 5 days ago, I submitted a pull request on Github which provides a new method for the array objects which is Array#indexes. I have fist edit the Array#index method in order it to return an array of indexes and not a single index (which is the first occurrence it finds). I found it more logical but a user (trans) tells us that it could break the contract of Array#index so I decided to move it into Array#indexes. Eric (drbrain) tells me I should reasonning why I want to add this method ; it's just a point of view : I don't really understand why Array#index return a single index if the parameter is in the array several times. Examples a = [1, 2, 3, 1] a.indexes(1) Return : [0, 3] a.index(1) Return : 0 In my opinion, it's not really logical, 1 is in the array twice Moreover, this pull request doesn't beak anything because we don't edit the Array#index method so programms which were created with previous version of Ruby will work. I hope my post is complete. Have a nice day. -- http://bugs.ruby-lang.org/