Given an array of arguments, how do I send those arguments to a particular function in Ruby?

Question

Forgive the beginner question, but say I have an array:

a = [1,2,3]

And a function somewhere; let's say it's an instance function:

class Ilike
  def turtles(*args)
    puts args.inspect
  end
end

How do I invoke Ilike.turtles with a as if I were calling (Ilike.new).turtles(1,2,3).

I'm familiar with send, but this doesn't seem to translate an array into an argument list.

A parallel of what I'm looking for is the Javascript apply, which is equivalent to call but converts the array into an argument list.

Solution

As you know, when you define a method, you can use the * to turn a list of arguments into an array. Similarly when you call a method you can use the * to turn an array into a list of arguments. So in your example you can just do:

Ilike.new.turtles(*a)

Comments

[Steven]

Fantastic. Based on your excellent answer, I've found a more thorough account of this technique in Wikibooks. This is actually perfectly reasonable given the parallel notation going the other other way. Oh, Ruby indeed. I've also noticed that you can prepend your own arguments without awkward a.unshift fidgeting by using Ilike.new.turtles(1,2,3,*a), although postpending seems to require such a manoeuver.

[Phrogz]

@StevenXu In Ruby 1.9 you can also splat for 'postpending'. a=[1,2]; b=[4,5]; p(0,*a,3,*b,6) #=> "0\n1\n2\n3\n4\n5\n6"

[RubyFanatic]

Fantastically answered!

[SourceSeeker]

This is a fun technique: some_func(*'some string of args'.split)