how to sort a ruby array of strings by length

Question

How do I sort this:

arr = ["aaa","aa","aaaa","a","aaaaa"];

into this

arr = ["a","aa","aaa","aaaa","aaaaa"];

Answer 1

arr = arr.sort_by {|x| x.length}

Or in 1.8.7+:

arr = arr.sort_by(&:length)