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Collin Dando
Collin Dando

Reputation: 13

How to best modify an array using .each

I am using Ruby, and I am relearning arrays and trying to better understand them. I know what they are but have never fully utilized them. I have an array, odds, and wanted to double every number in it. I came up with the below solution; however, I wanted to see if there was a more elegant/simple solution to my problem.

odds = [1,3,5,7,9]

odds.each do |x|
    odds[odds.index(x)]=x*2
end

end result is odds = [2,6,10,14,18]

Upvotes: 0

Views: 90

Answers (2)

Geoffrey Wiseman
Geoffrey Wiseman

Reputation: 5637

If you really want to modify in place, and you really want to use each, I guess your approach is as good as any. It doesn't feel idiomatic, but it does meet your stated constraints.

Here are some more common approaches:

Array.map

Mapping the array with map won't modify the original array (it's not in-place), which is often a good thing, but it might not be what you're looking for:

odds.map { |x| x*2 }

Array.map!

If you really do want to modify the original array, you can use map! to map in-place:

odds.map! { |x| x*2 }

Array.each_index

You did ask specifically about each, so if you want to use an each and you want to modify the original array, each_index might be your best bet:

odds.each_index { |i| odds[i] *= 2 }

Upvotes: 1

Sara Fuerst
Sara Fuerst

Reputation: 6098

You can use the map! enumerator to modify every item in an array: 

odds.map!{ |x| x*2}

Upvotes: 3

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