note 106056 added to function.array-search

Example of a recursive binary search that returns the index rather than boolean. <?php // returns the index of needle in haystack function binSearch($needle, $haystack) { // n is only needed if counting depth of search global $n; $n++; // get the length of passed array $l = count($haystack); // if length is 0, problem if($l <= 0) { return -1; } // get the mid element $m = (($l+($l%2))/2); // if mid >= length (e.g. l=1) if($m >= $l) { $m = $m-1; } // get the indexed element to compare to the passed element and branch accordingly $compare = $haystack[$m]; switch(true) { case($compare>$needle): { // recurse on the lower half $new_haystack = array_slice($haystack, 0, $m); $c = count($new_haystack); $r = binSearch($needle, $new_haystack); // return current index - (length of lower half - found index in lower half) return $m - ($c - $r); break; } case($compare<$needle): { // recurse on the upper half $new_haystack = array_slice($haystack, $m, ($l-$m)); $c = count($new_haystack); $r = binSearch($needle, $new_haystack); // return current position + found index in upper half return $m + $r; break; } case($compare==$needle): { // found it, so return index return $m; break; } } } ?> ---- Server IP: 69.147.83.197 Probable Submitter: 134.36.210.168 ---- Manual Page -- http://www.php.net/manual/en/function.array-search.php Edit -- https://master.php.net/note/edit/106056 Del: integrated -- https://master.php.net/note/delete/106056/integrated Del: useless -- https://master.php.net/note/delete/106056/useless Del: bad code -- https://master.php.net/note/delete/106056/bad+code Del: spam -- https://master.php.net/note/delete/106056/spam Del: non-english -- https://master.php.net/note/delete/106056/non-english Del: in docs -- https://master.php.net/note/delete/106056/in+docs Del: other reasons-- https://master.php.net/note/delete/106056 Reject -- https://master.php.net/note/reject/106056 Search -- https://master.php.net/manage/user-notes.php