Alex Sears

Iterating Backwards Through A Ruby Array

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Alex Sears

Developer. Drummer. Ginger.


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Iterating Backwards Through A Ruby Array

Posted by Alex Sears on .
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Iterating Backwards Through A Ruby Array

Posted by Alex Sears on .

This will be a quick one. I have seen alot of posts on StackOverflow about iterating backwards through a Ruby array. Ruby, in all its beauty, gives quite a few ways to iterate through an array.

Some of them are listed below:

disney = %w(Mickey Minnie Donald Goofy)

# using Array#each
disney.each { |val| puts val }

# using Enumerable#each_with_index
disney.each_with_index { |val, ind| puts "#{ind}: #{val}" }

# using Integer#times
disney.length.times { |ind| puts "#{ind}: #{disney[ind]}" }

These are just a few of the many ways. In other languages, iterating in the opposite direction can be kind of a pain in the…well you know. However, Ruby makes it a cinch. You can use the Array#reverse method to reverse the order of the elements in the array before iterating over them.

disney = %w(Mickey Minnie Donald Goofy)

# using Array#each
disney.reverse.each { |val| puts val }

# using Enumerable#each_with_index
disney.reverse.each_with_index { |val, ind| puts "#{ind}: #{val}" }

Boom! Yeah, it’s that easy.

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Alex Sears

http://alexsears.com

Developer. Drummer. Ginger.