Ruby iterator

Ruby iterator

Ruby each iterator

The each iterator returns all elements of the array or hash.

Grammar

collection.each do |variable|
   code
end

Code is executed for each element in the collection. Here, the collection can be an array or a hash.

#!/usr/bin/ruby

ary = [1,2,3,4,5]
ary.each do |i|
   puts i
end

This results in the following:

1
2
3
4
5

The each iterator is always associated with a block. I t returns each value of the array to the block, one after the other. The value is stored in variable i and then displayed on the screen.

Ruby collect iterator

The collect iterator returns all elements of the collection.

Grammar

collection = collection.collect

The collect method does not need to always be associated with a block. The collect method returns the entire collection, whether it is an array or a hash.

#!/usr/bin/ruby

a = [1,2,3,4,5]
b = Array.new
b = a.collect{ |x|x }
puts b

This results in the following:

1
2
3
4
5

Note: The collect method is not the correct way to copy between arrays. Here's another method called clone, which copies one array from one array to another.

You typically use the collect method when you want to do something with each value to get a new array. For example, the following code generates an array whose value is 10 times that of each value in a.

#!/usr/bin/ruby

a = [1,2,3,4,5]
b = a.collect{|x| 10*x}
puts b

This results in the following:

10
20
30
40
50