php - 有什么方法可以更快地提取字符串？

Question

我需要提取 HTTP 请求的虚拟主机名。 由于每个请求都会执行此操作，因此我正在寻找最快的方法来执行此操作。

下面的代码和时间只是我研究过的一些方式。

那么，有一些更快的方法可以做到这一点吗？

$hostname = "alphabeta.gama.com";

$iteractions = 100000;

//While Test

$time_start = microtime(true);
for($i=0;$i < $iteractions; $i++){
    $vhost = "";
    while(($i < 20) && ($hostname{$i} != '.')) $vhost .= $hostname{$i++};
}

$time_end = microtime(true);
$timewhile = $time_end - $time_start;

//Regexp Test
$time_start = microtime(true);
for($i=0; $i<$iteractions; $i++){
    $vhost = "";
    preg_match("/([A-Za-z])*/", $hostname ,$vals);
    $vhost = $vals[0];
}
$time_end = microtime(true);
$timeregex = $time_end - $time_start;

//Substring Test
$time_start = microtime(true);
for($i=0;$i<$iteractions;$i++){
    $vhost = "";
    $vhost = substr($hostname,0,strpos($hostname,'.'));
}
$time_end = microtime(true);
$timesubstr = $time_end - $time_start;

//Explode Test
$time_start = microtime(true);
for($i=0;$i<$iteractions;$i++){
    $vhost = "";
    list($vhost) = explode(".",$hostname);
}
$time_end = microtime(true);
$timeexplode = $time_end - $time_start;

//Strreplace Test. Must have the final part of the string fixed.
$time_start = microtime(true);
for($i=0;$i<$iteractions;$i++){
    $vhost = "";
    $vhost = str_replace(".gama.com","",$hostname);
}
$time_end = microtime(true);
$timereplace = $time_end - $time_start;

echo "While   :".$timewhile."\n";
echo "Regex   :".$timeregex."\n";
echo "Substr  :".$timesubstr."\n";
echo "Explode :".$timeexplode."\n";
echo "Replace :".$timereplace."\n";

作为结果时间:

While   :0.0886390209198
Regex   :1.22981309891
Substr  :0.338994979858
Explode :0.450794935226
Replace :0.33411693573

Answer 1

你可以试试 strtok() 函数:

$vhost = strtok($hostname, ".")

它比 while 循环的正确版本更快，并且可读性更高。