【程序】

<?php
runTimer();
$arr = array();
for ($i=0;$i<10000;$i++)
{
    $arr[$i] = $i;
}

runTimer('for() $arr[] = $i');
$str = serialize($arr);
runTimer('serialize($arr)');
$arr = unserialize($str);
runTimer('unserialize($str)');
$str=implode('|',$arr);
runTimer('implode');
$arr=explode('|',$str);
runTimer('explode');
echo "\r\n all is over \r\n";
function runTimer($str = '')
{ //统计时间
    static $st = 0;
    $mt = explode(' ', microtime());
    $ct = $mt[0] + $mt[1];
    if ($st)
        echo "$str: ", $ct - $st, "<br>";
    $st = $ct;
}
?>

【结果】
运行10000次所花的时间：
serialize: 0.00599408149719
unserialize: 0.00465297698975

implode: 0.0023980140686
explode: 0.00432395935059

运行100000次所花的时间：
serialize: 0.0741341114044
unserialize: 0.0589618682861

implode: 0.0294060707092
explode: 0.0475318431854

运行500000次所花的时间：
serialize: 0.581069946289
unserialize: 1.73503398895

implode: 0.160962104797
explode: 0.244714975357

【结论】
implode 和 explode 更快。