note 123204 added to function.array-intersect

If you have to intersect arrays of unique values then using array_intersect_key is about 20 times faster, just have to flip the key value pairs of the arrays, then flip the result again. <?php $one = range(1, 250000); $two = range(50000, 150000); $start = microtime(true); $intersection = array_intersect($one, $two); echo "Did it in ".( microtime(true) - $start )." seconds.\n"; $start = microtime(true); $intersection = array_flip(array_intersect_key(array_flip($one), array_flip($two))); echo "Did it in ".( microtime(true) - $start )." seconds.\n"; ?> Did it in 0.89163708686829 seconds. Did it in 0.038213968276978 seconds. ---- Server IP: 208.43.231.9 Probable Submitter: 88.132.196.188 ---- Manual Page -- http://php.net/manual/en/function.array-intersect.php Edit -- https://master.php.net/note/edit/123204 Del: integrated -- https://master.php.net/note/delete/123204/integrated Del: useless -- https://master.php.net/note/delete/123204/useless Del: bad code -- https://master.php.net/note/delete/123204/bad+code Del: spam -- https://master.php.net/note/delete/123204/spam Del: non-english -- https://master.php.net/note/delete/123204/non-english Del: in docs -- https://master.php.net/note/delete/123204/in+docs Del: other reasons-- https://master.php.net/note/delete/123204 Reject -- https://master.php.net/note/reject/123204 Search -- https://master.php.net/manage/user-notes.php