There is more fast implementation of array_diff, but with some limitations. If you need compare two arrays of integers or strings you can use such function:
public static function arrayDiffEmulation($arrayFrom, $arrayAgainst)
{
$arrayAgainst = array_flip($arrayAgainst);
foreach ($arrayFrom as $key => $value) {
if(isset($arrayAgainst[$value])) {
unset($arrayFrom[$key]);
}
}
return $arrayFrom;
}
It is ~10x faster than array_diff
php > $t = microtime(true);$a = range(0,25000); $b = range(15000,500000); $c = array_diff($a, $b);echo microtime(true) - $t;
4.4335179328918
php > $t = microtime(true);$a = range(0,25000); $b = range(15000,500000); $c = arrayDiffEmulation($a, $b);echo microtime(true) - $t;
0.37219095230103
