From: nobu@... Date: 2016-08-02T13:34:25+00:00 Subject: [ruby-core:76664] [Ruby trunk Feature#12648] `Enumerable#sort_by` with descending option Issue #12648 has been updated by Nobuyoshi Nakada. I prefer more descriptive option, e.g., `enum.sort_by(:descend) {|e| e}`. https://github.com/ruby/ruby/compare/trunk...nobu:feature/12648-sort_by-order ---------------------------------------- Feature #12648: `Enumerable#sort_by` with descending option https://bugs.ruby-lang.org/issues/12648#change-59884 * Author: Tsuyoshi Sawada * Status: Open * Priority: Normal * Assignee: ---------------------------------------- I would like to pass an optional argument to `Enumerable#sort_by` or `Enumerable#sort_by!` to allow descending sort. When the sort key is singular, this could be done by passing a single optinal boolean variable that represents ascending when `false` (default) and descending when `true`: ```ruby [3, 1, 2].sort_by(&:itself) # => [1, 2, 3] [3, 1, 2].sort_by(false, &:itself) # => [1, 2, 3] [3, 1, 2].sort_by(true, &:itself) # => [3, 2, 1] ``` When there are multiple sort keys, corresponding numbers of arguments should be passed: ```ruby [3, 1, 2, 0].sort_by{|e| [e % 2, e]} # => [0, 2, 1, 3] [3, 1, 2, 0].sort_by(false, false){|e| [e % 2, e]} # => [0, 2, 1, 3] [3, 1, 2, 0].sort_by(false, true){|e| [e % 2, e]} # => [2, 0, 3, 1] [3, 1, 2, 0].sort_by(true, false){|e| [e % 2, e]} # => [1, 3, 0, 2] [3, 1, 2, 0].sort_by(true, true){|e| [e % 2, e]} # => [3, 1, 2, 0] ``` -- https://bugs.ruby-lang.org/ Unsubscribe: