Ruby: Remove all instances of a duplicate value inside an array

Question

I have one array and I want to remove ALL instances of a duplicate value inside of that array.

arr = [1, 1, 2, 3, 4, 4, 5]

I want the expected output:

=> [2, 3, 5]

What would be the best way to do this?

Answer 1

p arr.group_by(&:itself).reject{|k,v|v.count>1}.keys

Output

[2, 3, 5]