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] . '...';
}

<?php
/*
  * @ Author: Lilov
  * @ Homepage: www.111cn.net
  * @ E-mail: zhongjiechao@gmail.com
  *
  */
$arr = array();
for($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>';
######################################
?>

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

if(isset($_GET["PHPSESSID"])){
session_id($_GET["PHPSESSID"]);
}
//启动一个session
session_start();

其他页面的获取方式为：
if(isset($_GET["PHPSESSID"])){
//设置当前的session为初始的session，session_id()一致即可
session_id($_GET["PHPSESSID"])
}
session_start();

index.php

<?
session_start();
  $_SESSION['name']="Aseoe";
  $sn = session_id();
  $url=".""index2.php?s=".$sn."">下一页";
  echo $url;
?>
 
index2.php
  $_GET[’s’]);   
  session_start();   
  echo "传递的session变量name的值为：".$_SESSION['name']; 
?>

$.ajax({
url: 'stat.php',

type: 'POST',

data:{Name:"keyun"},

dataType: 'html',

timeout: 1000,

error: function(){alert('Error loading PHP document');},

success: function(result){alert(result);}

});

pclose(popen("/home/xinchen/backend.php &", 'r'));

$ch = curl_init();
 
$curl_opt = array(CURLOPT_URL, 'http://www.111cn.net',
                            CURLOPT_RETURNTRANSFER, 1,
                            CURLOPT_TIMEOUT, 1,);
 
curl_setopt_array($ch, $curl_opt);
 
curl_exec($ch);
 
curl_close($ch);

<?php
header("content-type:text/html;charset=utf-8");
$pattern = preg_quote('天仙');//特殊字符自动添加转义符＼
$str = '宋夫人真是美若天仙';
echo preg_replace("/($pattern)/","<font color='blue'>$1</font>",$str);
?>

$msg = preg_replace("/<style>.+<＼/style>/is", "", $msg); -----删除<style></style>和中间的部分
$msg = preg_replace("/<[^>]+>/", "", $msg); -----是删除<>和中间的内容

eregi("<body([^>]+)>(.+)</body>",$data,$b)----察看$data中是否有body标签。如果有，把参数赋值$b[0]，中间部分赋值$b[1]。

<?php
class BookStore{
 private $p = array();

 function __set($name,$value){
  print "set:::::{$name}:{$value}<br />";
  $this->p[$name] = $value;
 }
 function __get($name){
  print "get:::::{$name}<br />";
  //array_key_exists检查给定的键名或索引是否存在于数组中
  return array_key_exists($name,$this->p) ? $this->p[$name] : null;
 }
}
$computer = new BookStore();
$computer->php = 'php web开发大全';
echo "php书籍=".$computer->php;
?>

<?php
 class MyClass{
  function printWeb(){
   echo "你现在访问的网站是www.111cn.net";
  }
 }
?>

general.inc.php文件

<?php
function __autoload($class_name){
 $file(dirname(__FILE__))."/libs/classes/$class_name.php";
 if (!file_exists($file)){
  return false;
 }else{
  require_once($file);
 }
}
?>

main.php

<?php
require("general.inc.php");
$obj = new Myclass();
if (is_object($obj)){
 $obj->printWeb();
}else{
 echo "类文件没调入";
}
?>