note 117115 added to function.rand

I agree with Sebmil (http://php.net/manual/en/function.array-rand.php#105265) that "array_rand()" produces weird and very uneven random distribution (as of my local PHP 5.3.8 and my public host's PHP 5.2.17). Unfortunately, I haven't got any access either to a server with the latest PHP version. My info is for those of you who like to check things for themselves and who don't believe all of the official statements in the docs. I've made a simple adjustment of his test code like this: <?php $s=1; // Start value $c=50; // Count / End value $test=array_fill($s, $c, 0); $ts=microtime(true); for($i=0; $i<5000000; $i++){ $idx=mt_rand($s, $c); // Try it with rand() - simpler but more evenly distributed than mt_rand() $test[$idx]++; } $te=microtime(true); $te=($te-$ts)*1000.0; // Loop time in miliseconds asort($test); echo "Test mt_rand() in ".$te." ms: <br/>\n"; foreach($test as $k=>$v) echo "$k :\t$v <br/>\n"; ?> And it appears to me that simple "$idx=rand(0, count($test)-1);" is much better than "$idx=array_rand($test, 1);". And what's more the simpler and a bit slower (0 ms up to total 712.357 ms at 5 mln cycles) "rand()" is better than "mt_rand()" in simple everyday use cases because it is more evenly distributed (difference least vs. most often numbers: ca. 0.20-1.28 % for "rand()" vs. ca. 1.43-1.68 % for "mt_rand()"). Try it for yourself... although it depends on your software and hardware configuration, range of numbers to choose from (due to random patterns), number of cycles in the loop, and temporary (public) server load as well. ---- Server IP: 72.52.91.14 Probable Submitter: 78.10.57.42 ---- Manual Page -- http://php.net/manual/en/function.rand.php Edit -- https://master.php.net/note/edit/117115 Del: integrated -- https://master.php.net/note/delete/117115/integrated Del: useless -- https://master.php.net/note/delete/117115/useless Del: bad code -- https://master.php.net/note/delete/117115/bad+code Del: spam -- https://master.php.net/note/delete/117115/spam Del: non-english -- https://master.php.net/note/delete/117115/non-english Del: in docs -- https://master.php.net/note/delete/117115/in+docs Del: other reasons-- https://master.php.net/note/delete/117115 Reject -- https://master.php.net/note/reject/117115 Search -- https://master.php.net/manage/user-notes.php