PHP循环函数foreach与while性能对比

/**
 * while跟foreach函数性能比较
 *
 */

// foreach 函数
foreach ($array as $key => $value) {
 echo $array[$key] = $value . '...';
}

// while 函数
while (list($key) = each($array)) {
 $array[$key] = $array[$key] . '...';
}

/*
  * @ Author: Lilov
  * @ Homepage: www.111com.net
  * @ E-mail: [email protected]
  *
  */
$arr = array();
for($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)

';
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)

';
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)

';
######################################
?>

测试结果：
将三次测试结果求平均值：
分别对应for、while、foreach
0.1311650
0.1666853
0.1237440