Blocks as Iterators

As mentioned earlier, one of the primary uses of blocks in Ruby is to provide iterators to which a range or list of items can be passed. Many standard classes such as Integer and Array have methods that can supply items over which a block can iterate. For example:

3.times{ |i| puts( i ) }
[1,2,3].each{|i| puts(i) }

You can, of course, create your own iterator methods to provide a series of values to a block. In the iterate1.rb program, I have defined a simple timesRepeat method that executes a block a specified number of times. This is similar to the times method of the Integer class except it begins at index 1 rather than at index 0 (here the variable i is displayed in order to demonstrate this):

iterate1.rb

def timesRepeat( aNum ...

Get The Book of Ruby now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.