So far we’ve learned one way to repeat an action in Ruby: using loops. As is often the case in Ruby, however, there’s more than one way to accomplish a given task. In this case, it’s also possible to repeat an action using an iterator.

An iterator is just a Ruby method that repeatedly invokes a block of code. The code block is just the bit that contains the instructions to be repeated, and those instructions can be just about anything you like!

The simplest iterator is the loop method. You can create a basic (but infinite!) loop by simply typing

loop { print "Hello, world!" }

In Ruby, curly braces ({}) are generally interchangeable with the keywords do (to open the block) and end (to close it). Knowing this, we can write a smarter loop than the one above:

i = 0
loop do
  i += 1
  print "#{i}"
  break if i > 5
end

The break keyword is our Get Out of Jail Free card: it breaks a loop as soon as its condition is met.