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.


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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: 
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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)


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