From: matz@... Date: 2019-09-02T07:02:47+00:00 Subject: [ruby-core:94735] [Ruby master Feature#15976] Add Array#overlap? for whether the intersection of 2 arrays is non empty? Issue #15976 has been updated by matz (Yukihiro Matsumoto). Status changed from Open to Feedback I don't think `overlap?` is a good name. Besides that, `Array#overlap?` creates an internal hash table anyway, so that it wouldn't solve the bottleneck. In this case, creating a hash table explicitly would perform better. Matz. ---------------------------------------- Feature #15976: Add Array#overlap? for whether the intersection of 2 arrays is non empty? https://bugs.ruby-lang.org/issues/15976#change-81351 * Author: fcheung (Frederick Cheung) * Status: Feedback * Priority: Normal * Assignee: * Target version: ---------------------------------------- This is semantically equivalent to `(ary1 & ary2).any?`, but more efficient and makes the intent more obvious. For example bundler [checks]( https://github.com/ruby/ruby/blob/master/lib/bundler/runtime.rb#L61 ) whether the list of requested groups and the list of groups for a dependency has any overlap - it doesn't care what the overlap is, as long as it is non empty In my personal projects we've found this to be a bottleneck when the arrays are large and where intersections are likely - `!(ary1 & ary2).empty?` keeps searching for all of the intersection even after we've found the first one, & creates extra garbage because of the intermediate array. See https://github.com/ruby/ruby/pull/2260 ---Files-------------------------------- 2260.patch (7.9 KB) -- https://bugs.ruby-lang.org/ Unsubscribe: