这个是从别人空间里看来的，不过自己还真从来没这么做过他们三者之间的比较，今天也学习了一下。

复制代码 代码如下:

<?php

$arr = array();

for($i = 0; $i < 50000; $i++){

$arr[] = $i*rand(1000,9999);

}

function GetRunTime()

{

list($usec,$sec)=explode(" ",microtime());

return ((float)$usec+(float)$sec);

}

/*=============================================*/

$time_start = GetRunTime();

for($i = 0; $i < count($arr); $i++){

$str = $arr[$i];

}

$time_end = GetRunTime();

$time_used = $time_end - $time_start;

echo 'Used time of for:'.round($time_used, 7).'(s)<br /><br />';

unset($str, $time_start, $time_end, $time_used);

/*=============================================*/

$time_start = GetRunTime();

while(list($key, $val) = each($arr)){

$str = $val;

}

$time_end = GetRunTime();

$time_used = $time_end - $time_start;

echo 'Used time of while:'.round($time_used, 7).'(s)<br /><br />';

unset($str, $key, $val, $time_start, $time_end, $time_used);

/*=============================================*/

$time_start = GetRunTime();

foreach($arr as $key => $val){

$str = $val;

}

$time_end = GetRunTime();

$time_used = $time_end - $time_start;

echo 'Used time of foreach:'.round($time_used, 7).'(s)<br /><br />';

?>