Question

>> [1, 2, 3, 4, 5].any? {|n| n % 3 == 0}
=> true

What if I want to know which item matched, not just whether an item matched? I’m only interested in short-circuiting solutions (those that stop iterating as soon as a match is found).

I know that I can do the following, but as I’m new to Ruby I’m keen to learn other options.

>> match = nil
=> nil
>> [1, 2, 3, 4, 5].each do |n|
..   if n % 3 == 0
..     match = n
..     break
..   end
.. end
=> nil
>> match
=> 3

Answer 1

Are you looking for this:

[1, 2, 3, 4, 5].find {|n| n % 3 == 0} # => 3

From the docs:

Passes each entry in enum to block. Returns the first for which block is not false.

So this would also fulfill your ‘short-circuiting’ requirement. Another, probably less common used alias for Enumerable#find is Enumerable#detect, it works exactly the same way.