Re: in_array algorithm

On Wed, 2002-02-06 at 08:26, John Fulton wrote: > > Does anyone know which algorithm in_array() uses? > > For example, if I say > > in_array("foo", $arr) > > Does in_array() do an unordered sequential serach of $arr for > "foo" which takes up to n comparisons [where n = count($arr)], > or does it do a binary search which takes about lg(n) comparisons? > Is it up to me to maintain a sorted array in the later case? > > Thanks, > John Well, the source for the currect version of that function (as of 4.2.0-dev) is here: http://cvs.php.net/co.php/php4/ext/standard/array.c?r=1.156 Search down the page for 'php_search_array'--that's the function which actually does the searching. Looks like a simple sequential search to me. Torben -- Torben Wilson <torben@php.net> http://www.thebuttlesschaps.com http://www.hybrid17.com http://www.inflatableeye.com +1.604.709.0506