CODEWITHSUNDEEP
arraysruby
adbarads
adbarads

Reputation: 1303

How to find all array elements that match both arrays

Is there an easy way to iterate through 2 arrays and find any element values that are exactly the same in both arrays and populate it into a new array?

For example:

arr_a = ["a","b","c","d"]

arr_b = ["123","456","b","d","c"]

The array I want to create would be:

new_arr = ["b","c","d"]

I tried this:

another_arr = [*arr_a, *arr_b] #combines the 2 arrays
another_arr.select { |e| another_arr.count(e) >1 }.uniq #then find all dupes

but I don't know how to push the results to an array.

Is this the right way of going about it? Are there any ideas how push the results to an array?

Upvotes: 0

Views: 89

Answers (2)

Sam Farmer
Sam Farmer

Reputation: 176

What you are attempting to do is a Set Intersection, which can be achieved in Ruby using the & operator. 

arr_a = ["a","b","c","d"]

arr_b = ["123","456","b","d","c"]

new_array = arr_a & arr_b

Read more about this in "ary & other_ary".

Upvotes: 5

Ursus
Ursus

Reputation: 30056

You're looking for intersection of two sets. This is way simpler:

arr_a & arr_b

Upvotes: 1

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