What's the fastest way in Ruby to get the first enumerable element for which a block returns true?

Several core ruby classes, including Array and Hash include the Enumerable module which provides many useful methods to work with these enumerations.

This module provides the find or detect methods which do exactly what you want to achieve:

arr = [12, 88, 107, 500]
arr.find { |num| num > 100 } # => 107

Both method names are synonyms to each other and do exactly the same.

arr.find{|el| el>100} #107 (or detect; it's in the Enumerable module.)