On Mon, January 29, 2007 11:20 am, Ken Dozier wrote:
> Does in_array() use a search algorithm (i.e., binary search), or does
> it
> check sequentially each element in the array?
Since there is no guarantee that the elements are in any particular
order, it almost has to be sequential...
> I am using in_array() within a while{} loop to check query results
> against
> an access-list array to produce a third array containing items that
> successfully passed the comparison test. Because the two starting
> arrays in
> the worst-case scenario can have 8,000 items each, the loop is timing
> out.
> Advice or alternative methods are appreciated.
>
> Code Sample:
> <?php
> function check_results($results, $access_list)
> { # Check for $results in array $access_list and
> # add matches to array $match.
>
> $result = false;
> $match = array();
>
> while ($r = mysql_fetch_row($results))
> { if ( in_array($r[0], $access_list) )
> { $match[] = $r; }
> }
>
> if ( count($match) > 0 ) { $result = $match; }
>
> return $result;
> }
> ?>
Ideal #1:
Figure out how to write an SQL query to find what's in the DB, and
don't do any search in PHP at all.
Ideal #2:
Put the values in as keys, and use http://php.net/isset
This will "hash" the values and have an O(1) lookup, I think.
Only works if you know the uniqueness of the values to be searched, or
don't care about duplicates.
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