note 119645 deleted from function.abs by salathe
| From: | salathe@php.net | Date: | Mon, 21 Sep 2020 14:29:01 +0000 |
| Subject: | note 119645 deleted from function.abs by salathe | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-215175@lists.php.net to get a copy of this message | ||
Note Submitter: eep2004 at ukr dot net
----
<?php
$arr = array();
for ($i = 0; $i < 1000; $i++) $arr[] = rand(-100, 100);
$start = microtime(true);
for ($i = 0; $i < 1000; $i++){
foreach ($arr as $v) $v = abs($v);
}
echo number_format(microtime(true) - $start, 4).'<br />';
$start = microtime(true);
for ($i = 0; $i < 1000; $i++){
foreach ($arr as $v) if ($v < 0) $v = abs($v);
}
echo number_format(microtime(true) - $start, 4).'<br />';
$start = microtime(true);
for ($i = 0; $i < 1000; $i++){
foreach ($arr as $v) if ($v < 0) $v *= -1;
}
echo number_format(microtime(true) - $start, 4).'<br />';
?>
Result:
1.4061
0.9697
0.2805
Conclusion: better to check before using the feature that the number is less than zero. Even better
use multiplication by -1 than this function.