note 60268 added to function.array-rand

Here's an algorithm to make a weighted selection of an item from an array. Say we have an array $items with keys as items and values as corresponding weights. For example: <?php $items = array( item1 => 3, item2 => 4, item3 => 5, ); ?> i.e. we want to choose item1 25% of the time, item2 33.3% of the time and item3 41.6% of the time. Here's a function that works when the weights are positive integers: <?php function array_rand_weighted($values) { $r = mt_rand(1, array_sum($values)); foreach ($values as $item => $weight) { if ($r <= $weight) return $item; $r -= $weight; } } ?> Enjoy! ---- Manual Page -- http://www.php.net/manual/en/function.array-rand.php Edit -- http://master.php.net/manage/user-notes.php?action=edit+60268 Delete: added to the manual -- http://master.php.net/manage/user-notes.php?action=delete+60268&report=yes&reason=added+to+the+manual Delete: bad code -- http://master.php.net/manage/user-notes.php?action=delete+60268&report=yes&reason=bad+code Delete: spam -- http://master.php.net/manage/user-notes.php?action=delete+60268&report=yes&reason=spam Delete: useless -- http://master.php.net/manage/user-notes.php?action=delete+60268&report=yes&reason=useless Delete: non-english -- http://master.php.net/manage/user-notes.php?action=delete+60268&report=yes&reason=non-english Delete: already in docs -- http://master.php.net/manage/user-notes.php?action=delete+60268&report=yes&reason=already+in+docs Delete: other reasons -- http://master.php.net/manage/user-notes.php?action=delete+60268&report=yes Reject -- http://master.php.net/manage/user-notes.php?action=reject+60268&report=yes Search -- http://master.php.net/manage/user-notes.php