The Book of Ruby

Iterating upto and downto

If you need to count from a specific low value up to a high value, you may use the upto() method of an integer. A block argument may optionally be used if you want to display the value at each iteration:

upto_downto.rb

0.upto(10) do
    | i |
    puts( i )
end

The previous code displays the integers 0 to 10. You may also count down from a high to a low value using the downto() method:

10.downto(0) do
    | i |
    puts( i )
end

As you can probably guess, this code displays 10 to 0.