Feature #21678: Enumerable#rfind

• Status: Open
• Assignee: -
• Target version: -

[kddnewton (Kevin Newton)]

I'd like to introduce rfind to enumerable, which would effectively be the same as reverse_each.find. I've found myself using this a surprising number of times, and have been surprised at its omission. That means either falling back to reverse_each or rindex.

For context, here are a couple of examples of this in the wild:

• pry
• bundler
• textbringer

[nobu (Nobuyoshi Nakada)]

https://github.com/nobu/ruby/tree/refs/heads/enum-rfind

[matz (Yukihiro Matsumoto)]

The Enumerable module basically relies on the #each method which only works in the forward direction, and the only way to scan backwards is to convert it to an array once. I agree with Array#rfind (which can be implemented efficiently), but is it necessary for the Enumerable module as well?

Matz.

[kddnewton (Kevin Newton)]

That makes sense! I'm totally fine with it just being on Array.

[kddnewton (Kevin Newton)]

https://github.com/ruby/ruby/pull/15189