I think "purely functional, not a single re-assigned variable" often introduces significant extra complexity, when Ruby is a language that embraces both functional and imperative programming.

One of my favorite aspects of Ruby is how easy it is to write in a functional programming style, and including the scan operation would expand the number of use cases covered by functional methods.

If you like the functional style of programming, though, you’ll find a lot more facilities for it in Rust, because Rust has a lot more facilities than Go in general.

Another option is the use the functional library Ramda, while the syntax may be a bit different from the Ruby and Pure JS version, I find it to be more declarive: list = [null, "say", "kenglish", "co", null] R.reject(R.isNil, list) // return new array [ 'say', 'kenglish', 'co' ]

multi-paradigm: functional, imperative

But now, you can do the same thing in functional style!

Brings functional programming to Python land