Array#rotate equivalent in ruby 1.8.7

Question

a = [ "a", "b", "c", "d" ]
a.rotate         #=> ["b", "c", "d", "a"]

#rotate is a method of Array in Ruby 1.9. I want this functionality in Ruby 1.8.7. What is the ideal code?

Answer 1

If you require 'backports/1.9.2/array/rotate', you will get Array#rotate and rotate! in older versions of Ruby.

Either way, you avoid reinventing the wheel, and more importantly you gain the advantage of an implementation that passes RubySpec. It will work for all corner cases and ensure compatibility with Ruby 1.9.

For example, none of the two answers given work for []!