note 117289 added to function.array-intersect
| From: | yuvalatvisualdomainsdotcom | Date: | Sun, 17 May 2015 13:17:31 +0000 |
| Subject: | note 117289 added to function.array-intersect | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-202576@lists.php.net to get a copy of this message | ||
Using isset to achieve this, is many times faster:
<?php
$m = range(1,1000000);
$s = [2,4,6,8,10];
// Use array_intersect to return all $m values that are also in $s
$tstart = microtime(true);
print_r (array_intersect($m,$s));
$tend = microtime(true);
$time = $tend - $tstart;
echo "Took $time";
// Use array_flip and isset to return all $m values that are also in $s
$tstart = microtime(true);
$f = array_flip($s);
/* $f now looks like this:
(
[2] => 0
[4] => 1
[6] => 2
[8] => 3
[10] => 4
)
*/
// $u will hold the intersected values
$u = [];
foreach ($m as $v) {
if (isset($f[$v])) $u[] = $v;
}
print_r ($u);
$tend = microtime(true);
$time = $tend - $tstart;
echo "Took $time";
?>
Results:
Array
(
[1] => 2
[3] => 4
[5] => 6
[7] => 8
[9] => 10
)
Took 4.7170009613037
(
[0] => 2
[1] => 4
[2] => 6
[3] => 8
[4] => 10
)
Took 0.056024074554443
array_intersect: 4.717
array_flip+isset: 0.056
----
Server IP: 72.52.91.14
Probable Submitter: 81.218.139.3
----
Manual Page -- http://php.net/manual/en/function.array-intersect.php
Edit -- https://master.php.net/note/edit/117289
Del: integrated -- https://master.php.net/note/delete/117289/integrated
Del: useless -- https://master.php.net/note/delete/117289/useless
Del: bad code -- https://master.php.net/note/delete/117289/bad+code
Del: spam -- https://master.php.net/note/delete/117289/spam
Del: non-english -- https://master.php.net/note/delete/117289/non-english
Del: in docs -- https://master.php.net/note/delete/117289/in+docs
Del: other reasons-- https://master.php.net/note/delete/117289
Reject -- https://master.php.net/note/reject/117289
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