note 82144 added to function.array-diff

Quoting Hayley Watson's note sent @ 17-Oct-2007 02:55 -------------------------------------------------------------------- A wee idiom for KEEPING only those elements of an array $a that appear in an array $b (without introducing any elements of $b that do not appear in $a). <?php array_diff($a, array_diff($a, $b)) ?> ... -------------------------------------------------------------------- Um... this is really unnecessary. You just have to do this: <?php array_intersect($a, $b) ?> An intersection of sets A and B is logically equivalent to the difference of set A and the difference of set A and B Written a little more "mathematically" using "&" as the symbol for intersection instead of the "proper" one (which looks like an upside down U ): (A & B) == A - (A - B) ---- Server IP: 209.41.74.194 Probable Submitter: 65.117.116.130 ---- Manual Page -- http://www.php.net/manual/en/function.array-diff.php Edit -- https://master.php.net/note/edit/82144 Del: integrated -- https://master.php.net/note/delete/82144/integrated Del: useless -- https://master.php.net/note/delete/82144/useless Del: bad code -- https://master.php.net/note/delete/82144/bad+code Del: spam -- https://master.php.net/note/delete/82144/spam Del: non-english -- https://master.php.net/note/delete/82144/non-english Del: in docs -- https://master.php.net/note/delete/82144/in+docs Del: other reasons-- https://master.php.net/note/delete/82144 Reject -- https://master.php.net/note/reject/82144 Search -- https://master.php.net/manage/user-notes.php