note 82143 added to function.array-diff

As touched on in kitchin's comment of 19-Jun-2007 03:49 and nilsandre at gmx dot de's comment of 17-Jul-2007 10:45, array_diff's behavior may be counter-intuitive if you aren't thinking in terms of set theory. array_diff() returns a *mathematical* difference (a.k.a. subtraction) of elements in array A that are in array B and *not* what elements are different between the arrays (i.e. those that elements that are in either A or B but aren't in both A and B). Drawing one of those Ven diagrams or Euler diagrams may help with visualization... As far as a function for returning what you may be expecting, here's one: <?php function array_xor ($array_a, $array_b) { $union_array = array_merge($array_a, $array_b); $intersect_array = array_intersect($array_a, $array_b); return array_diff($union_array, $intersect_array) } ?> ---- Server IP: 209.41.74.194 Probable Submitter: 12.47.22.186 ---- Manual Page -- http://www.php.net/manual/en/function.array-diff.php Edit -- https://master.php.net/note/edit/82143 Del: integrated -- https://master.php.net/note/delete/82143/integrated Del: useless -- https://master.php.net/note/delete/82143/useless Del: bad code -- https://master.php.net/note/delete/82143/bad+code Del: spam -- https://master.php.net/note/delete/82143/spam Del: non-english -- https://master.php.net/note/delete/82143/non-english Del: in docs -- https://master.php.net/note/delete/82143/in+docs Del: other reasons-- https://master.php.net/note/delete/82143 Reject -- https://master.php.net/note/reject/82143 Search -- https://master.php.net/manage/user-notes.php