From: daniel@...42.com Date: 2020-03-15T15:37:47+00:00 Subject: [ruby-core:97507] [Ruby master Feature#16665] Add an Array#except_index method Issue #16665 has been updated by Dan0042 (Daniel DeLorme). alex_golubenko (Alex Golubenko) wrote in #note-10: > I also heard from developers, that they faced tricky challenges where this method could help. :) Then it would be really nice if you could show these tricky challenges here; that would be the best argument in favor. ---------------------------------------- Feature #16665: Add an Array#except_index method https://bugs.ruby-lang.org/issues/16665#change-84656 * Author: alex_golubenko (Alex Golubenko) * Status: Open * Priority: Normal ---------------------------------------- The main idea is to implement a method that we can use to exclude elements from the array by their indices. For example: ``` ruby %w( a b c d e f).except_index(0, -1) => ["b", "c", "d", "e"] %w( a b c d e f g h ).except_index(0..1, 3, -2..-1) => ["c", "e", "f"] ``` I was meeting many questions on the StackOverflow about how to do such functionality also found many topics about it. So I think it might a helpful addition. I spent a few days finding the proper solution on Ruby that might be acceptable with integers and ranges(both positive and negative) and has good performance: ```ruby def except_index(*indexes) indexes.each_with_object(dup) do |ind, obj| ind.is_a?(Range) ? ind.each { |i| obj[i] = false } : obj[ind] = false end.select(&:itself) end ``` As you can see it's have not the best readability so I think it's a good point to add a built-in method on C. -- https://bugs.ruby-lang.org/ Unsubscribe: