note 111252 added to function.mt-rand

Useful way to use the: <?php /** * Returns a random key, the probability of which is calculated according to a weighting factor. * weightedIndex(array(90,10)) with a probability of 90% will return 0, and a 10% return 1 * weightedIndex(array('a'=>5,'b'=>9.5,'c'=>85.5)) with a probability of 85.5% of the returns 'c' * * @param array $p an array of keys and their corresponding probabilities * * @return mixed random array key */ function weightedIndex( array $p ) { $maxWeight = array_sum( $p ); $indexes = array_keys( $p ); $rand = mt_rand() / mt_getrandmax() * $maxWeight; $count = count( $p ); $prevp = 0; // do not check the last item, as if previous not worked, it will return the default for ( $i = 0; $i < $count - 1; $i++ ) { if ( $p[$indexes[$i]] == 0 ) { continue; } $p[$indexes[$i]] += $prevp; if ( $rand <= $p[$indexes[$i]] ) { return $indexes[$i]; } $prevp = $p[$indexes[$i]]; } return $indexes[$count - 1]; } ?> ---- Server IP: 69.147.83.199 Probable Submitter: 195.24.142.156 ---- Manual Page -- http://php.net/manual/en/function.mt-rand.php Edit -- https://master.php.net/note/edit/111252 Del: integrated -- https://master.php.net/note/delete/111252/integrated Del: useless -- https://master.php.net/note/delete/111252/useless Del: bad code -- https://master.php.net/note/delete/111252/bad+code Del: spam -- https://master.php.net/note/delete/111252/spam Del: non-english -- https://master.php.net/note/delete/111252/non-english Del: in docs -- https://master.php.net/note/delete/111252/in+docs Del: other reasons-- https://master.php.net/note/delete/111252 Reject -- https://master.php.net/note/reject/111252 Search -- https://master.php.net/manage/user-notes.php