Ruby access multiple array elemenets by indexes (sub array)

Question

I have an array and I have an array with indexes of certain elements from the first array. What is the best way to get the elements from the first array?

I am doing:

result = []
indexes.each { |current| result << my_array[current] }

But there should be a better way..

Samsinite · Accepted Answer · 2013-02-02 21:08:01Z

44

You can use Array#map:

indexes.map { |i| my_array[i] }

Or even better, Array#values_at

my_array.values_at(*indexes)

Where the * symbol extracts the array into arguments that get passed to the method.

answered Feb 2, 2013 at 21:08

Samsinite

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2 Comments

bliof Over a year ago

I knew I was missing something 10x :)

Alexander Gorg Over a year ago

values_at is the fastest, by the way. By benchmark results it is ~ 2x faster than map and push, nevertheless, it's less 'human'.

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