From: sawadatsuyoshi@... Date: 2020-04-04T06:10:28+00:00 Subject: [ruby-core:97714] [Ruby master Feature#5663] Combined map/select method Issue #5663 has been updated by sawa (Tsuyoshi Sawada). I think this proposal has been realized under the name `Enumerable#filter_map` following the duplicate proposal #15323. So it should be closed. ---------------------------------------- Feature #5663: Combined map/select method https://bugs.ruby-lang.org/issues/5663#change-84921 * Author: wycats (Yehuda Katz) * Status: Assigned * Priority: Normal * Assignee: matz (Yukihiro Matsumoto) ---------------------------------------- It is pretty common to want to map over an Enumerable, but only include the elements that match a particular filter. A common idiom is: enum.map { |i| i + 1 if i.even? }.compact It is of course also possible to do this with two calls: enum.select { |i| i.even? }.map { |i| i + 1 } Both cases are clumsy and require two iterations through the loop. I'd like to propose a combined method: enum.map_select { |i| i + 1 if i.even? } The only caveat is that it would be impossible to intentionally return nil here; suggestions welcome. The naming is also a strawman; feel free to propose something better. -- https://bugs.ruby-lang.org/ Unsubscribe: