sample (Array)

Ruby quick tip: want to get a random element from an Array? Use Array#sample

Choose a random element or n random elements from the array. The elements are chosen by using random and unique indices into the array in order to ensure that an element doesn’t repeat itself unless the array already contained duplicate elements. If the array is empty the first form returns nil and the second form returns an empty array. If rng is given, it will be used as the random number generator.

Full article: http://apidock.com/ruby/Array/sample