note 111563 added to function.array-intersect

I bench-marked some uses of array_intersect and can't believe how slow it is. This isn't as elaborate, but handles most cases and is much faster: <?php /** examines two arrays and returns the intersected arrays with matching keys (ignores duplicate keys) */ function simple_array_intersect($a,$b) { $a_assoc = $a != array_values($a); $b_assoc = $b != array_values($b); $ak = $a_assoc ? array_keys($a) : $a; $bk = $b_assoc ? array_keys($b) : $b; $out = array(); for ($i=0;$i<sizeof($ak);$i++) { if (in_array($ak[$i],$bk)) { if ($a_assoc) { $out[$ak[$i]] = $a[$ak[$i]]; } else { $out[] = $ak[$i]; } } } return $out; } ?> You can try this out with this: <?php // create a large array (simple) $first = array(); for ($i=500;$i<500000;$i++) { $first[] = $i; } // create a smaller array (associative) $second = array(); for ($i=499990;$i<500000;$i++) { $second[$i] = rand(); } echo microtime(true)."\n"; // built-in function print_r(array_intersect($first,$second)); echo microtime(true)."\n"; // favour simple array as match print_r(simple_array_intersect($first,$second)); echo microtime(true)."\n"; // favour associative keys for match print_r(simple_array_intersect($second,$first)); echo microtime(true)."\n"; ?> ---- Server IP: 69.147.83.199 Probable Submitter: 99.241.44.202 ---- Manual Page -- http://php.net/manual/en/function.array-intersect.php Edit -- https://master.php.net/note/edit/111563 Del: integrated -- https://master.php.net/note/delete/111563/integrated Del: useless -- https://master.php.net/note/delete/111563/useless Del: bad code -- https://master.php.net/note/delete/111563/bad+code Del: spam -- https://master.php.net/note/delete/111563/spam Del: non-english -- https://master.php.net/note/delete/111563/non-english Del: in docs -- https://master.php.net/note/delete/111563/in+docs Del: other reasons-- https://master.php.net/note/delete/111563 Reject -- https://master.php.net/note/reject/111563 Search -- https://master.php.net/manage/user-notes.php