Re: performance with looping and count()ing

Hi, Saturday, March 27, 2004, 4:45:38 AM, you wrote: CWP> hi. CWP> ok, so i've always been under the impression that count()ing during the CWP> expression of a loop was much inefficient when compared to count()ing CWP> just before the loop expression. CWP> GOOD: CWP> <?php CWP> $the_array_cnt = count($the_array); CWP> for($i = 0; $i < $the_array_cnt; $i++) CWP> { CWP> ... CWP> } ?>> CWP> BAD: CWP> <?php CWP> for($i = 0; $i < count($the_array); $i++) CWP> { CWP> ... CWP> } ?>> CWP> but then i did some tests and found that only on very large arrays is CWP> there any difference between the two. count()ing outside of the loop was CWP> only marginally better. CWP> i also tried performing the same operation using foreach() and it was CWP> slightly faster than count()ing within the loop and slightly slower than CWP> count()ing outside the loop. CWP> somone pointed out in a post to a message board that php handles the CWP> result of a count() in a special way and so it therefore does not need CWP> to count the array more than once each pass through the loop? can CWP> someone confirm? CWP> thanks, CWP> chris. CWP> -- CWP> PHP General Mailing List (http://www.php.net/) CWP> To unsubscribe, visit: http://www.php.net/unsub.php Depends on your code logic, if $the_array gets modified in the loop then you have to check it on each pass. If not, efficiency would suggest doing it before the loop. You can always do the 1 line version: for ($i=0,$j=count($the_array);$i<$j;$i++){ -- regards, Tom