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 R

Answer 1

For the rotate! version without the parameter, gnab's is good. If you want the non-destructive one, with an optional parameter:

class Array
  def rotate n = 1; self[n..-1]+self[0...n] end
end

If n may become larger than the length of the array:

class Array
  def rotate n = 1; return self if empty?; n %= length; self[n..-1]+self[0...n] end
end