This is your example in Ruby: isLarge = -> {|a| a > 100 } numbers.filter(&isLarge) Or you could replace the first line: isLarge = -> { _1 > 100

This is your example in Ruby: isLarge = -> {|a| a > 100 } numbers.filter(&isLarge) Or you could replace the first line: isLarge = -> { _1 > 100 } Some people hate that syntax, though. I think for trivial predicates like this, it's fine.