How to remove all instances of duplicated values from an array

Question

I know there is array_unique function, but I want to remove duplicates. Is there a built-in function or do I have to roll my own.

Example input:

banna, banna, mango, mango, apple

Expected output:

apple

Answer 1

You can use a combination of array_unique, array_diff_assoc and array_diff:

array_diff($arr, array_diff_assoc($arr, array_unique($arr)))