Question

There are 3 operations with sets in mathematics: intersection, difference and union (unification). In PHP we can do this operations with arrays:

• intersection: array_intersect
• difference: array_diff

What function is for union?

No duplicates can be in the result array (like array_intersect and array_diff).

If indexes are numeric then array_merge will not overwrite the original value, but will be appended (PHP docs).

Answer 1

Try array_merge:

array_unique(array_merge($array1, $array2));

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