php相关函数测试

最新推荐文章于 2025-12-10 11:19:03 发布

原创最新推荐文章于 2025-12-10 11:19:03 发布 · 769 阅读

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#php #testing #测试 #2010 #ini

本文通过对比PHP中foreach与for循环的性能，以及sizeof与count函数的效率差异，展示了不同循环方式对内存使用和运行时间的影响。

作者：SNAIL_RUN
时间：2009-4-15
博客：http://blog.youkuaiyun.com/SNAIL_RUN

测试环境:php-fastcgi 5.2.6

测试代码:

<?php require_once '../common/file.inc.php'; set_time_limit(0); ini_set("memory_limit","-1"); $arr = array(); $num = 1000000; echo "Populating test array with" . $num . " elements ..."; for($i=0;$i<$num;$i++) { $arr[$i] = microtime(true) . mt_rand(); } echo "Populated./n/n"; echo "Start testing Foreach .... /n"; $start_time = microtime(true); foreach($arr as $key => $val) { $res = isset($arr[$key]); } echo "Foreach result:" . (microtime(true) - $start_time) . "/n/n"; echo "memory allocate: " . XJfile::size_format(memory_get_usage()) . "/n/n"; echo "Start testing regular for as follow..../n"; $start_time = microtime(true); for($i = 0;$i<sizeof($arr);$i++) { $res = isset($arr[$i]); } echo "For result:" . (microtime(true) - $start_time) . "/n/n"; echo "memory allocate: " . XJfile::size_format(memory_get_usage()) . "/n/n"; echo "Start testing regular count for as follow..../n"; $start_time = microtime(true); for($i = 0;$i<count($arr);$i++) { $res = isset($arr[$i]); } echo "For result:" . (microtime(true) - $start_time) . "/n/n"; echo "memory allocate: " . XJfile::size_format(memory_get_usage()) . "/n/n"; echo "Starting test for pre_computed size Array for ... /n"; $start_time = microtime(true); $count = sizeof($arr); for($i = 0;$i<$count;$i++) { $res = isset($arr[$i]); } echo "Pre_computed size array For result:" . (microtime(true) - $start_time) . "/n/n"; echo "memory allocate: " . XJfile::size_format(memory_get_usage()) . "/n/n";

上面的代码主要涉及foreach与for的速度比较,sizeof与count的比较.

我们先可设1000000(1百万显示结果如下)

X-Powered-By: PHP/5.2.6 Content-type: text/html Populating test array with1000000 elements ...Populated. Start testing Foreach .... Foreach result:0.269654989243 memory allocate: 168.33617MB Start testing regular for as follow.... For result:0.595597982407 memory allocate: 168.33633MB Start testing regular for as follow.... For result:0.580011844635 memory allocate: 168.33633MB Starting test for pre_computed size Array for ... Pre_computed size array For result:0.191917181015 memory allocate: 168.33633MB

1.可见foreach明显比for循环慢，测试结果中的第二项耗时最长，主要是由于把sizeof用在了for循环中，导致了php额外分配了一些资源去处理.

2.sizeof比count稍快,但效果不明显

当我们设为500万时效果更明显

X-Powered-By: PHP/5.2.6 Content-type: text/html Populating test array with5000000 elements ...Populated. Start testing Foreach .... Foreach result:1.63449788094 memory allocate: 865.20081MB Start testing regular for as follow.... For result:3.02416491508 memory allocate: 865.20100MB Starting test for pre_computed size Array for ... Pre_computed size array For result:1.01491594315 memory allocate: 865.20100MB

其它测试待续