php array_diff
PHP function array_diff(array $array1, array $array2, array ...$_) int[]
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Computes the difference of arrays.
Parameters:
array--$array1--The array to compare from
array--$array2--An array to compare against
array--...$_--[optional]
Returns: an array containing all the entries from array1 that are not present in any of the other arrays.