php preg_replace函数基础与实例代码
preg_replace(mixed $pattern,mixed $replacement,mixed $subject [, int $limit = -1 [, int &$count ]])主题为匹配搜索模式,替换要搜索的模式,它可以是一个字符串或一个字符串数组.
电子修饰符使preg_replace函数()替代后,适当引用作为参数是php代码进行替换,提示:请确保置换构成一个有效的php代码字符串,否则php将在包含preg_replace函数线()解析错误.
返回值:preg_replace函数()返回一个数组,如果这个问题的参数是一个数组或一个字符串,否则,如果找到匹配,新问题会产生,否则将返回主题不变或null如果发生错误.
实例一,代码如下:
- $string = 'april 15, 2003';
- $pattern = '/(w+) (d+), (d+)/i';
- $replacement = '${1}1,$3';
- echo preg_replace($pattern, $replacement, $string);
实例二,代码如下:
- $string = 'the quick brown fox jumped over the lazy dog.';
- $patterns = array();
- $patterns[0] = '/quick/';
- $patterns[1] = '/brown/';
- $patterns[2] = '/fox/';
- $replacements = array();
- $replacements[2] = 'bear';
- $replacements[1] = 'black';
- $replacements[0] = 'slow';
- echo preg_replace($patterns, $replacements, $string);
通过ksorting模式和替代,我们应该得到我们想要的,代码如下:
- ksort($patterns);
- ksort($replacements);
- echo preg_replace($patterns, $replacements, $string);
更换几个值,代码如下:
- $patterns = array ('/(19|20)(d{2})-(d{1,2})-(d{1,2})/',
- '/^s*{(w+)}s*=/');
- $replace = array ('//', '$ =');
- echo preg_replace($patterns, $replace, '{startdate} = 1999-5-27');
过滤所有html标签,代码如下:
- preg_replace("/(</?)(w+)([^>]*>)/e",
- "'\1'.strtoupper('\2').'\3'",
- $html_body);
过滤所有script,代码如下:
- $user_agent = "mozilla/4.0 (compatible; msie 5.01; windows nt 5.0)";
- $ch = curl_init(); // initialize curl handle
- curl_setopt($ch, curlopt_url, $url); // set url to post to
- curl_setopt($ch, curlopt_failonerror, 1); // fail on errors
- curl_setopt($ch, curlopt_followlocation, 1); // allow redirects
- curl_setopt($ch, curlopt_returntransfer,1); // return into a variable
- curl_setopt($ch, curlopt_port, 80); //set the port number
- curl_setopt($ch, curlopt_timeout, 15); // times out after 15s
- curl_setopt($ch, curlopt_useragent, $user_agent);
- $document = curl_exec($ch);
- $search = array('@<script[^>]*?>.*?</script>@si', // strip out javascript教程 www.111cn.net
- '@<style[^>]*?>.*?</style>@siu', // strip style tags properly
- '@<[/!]*?[^<>]*?>@si', // strip out html tags
- '@<![ss]*?–[ ]*>@', // strip multi-line comments including cdata
- '/s{2,}/',
- );
- $text = preg_replace($search, " ", html_entity_decode($document));
- $pat[0] = "/^s+/";
- $pat[2] = "/s+$/";
- $rep[0] = "";
- $rep[2] = " ";
- $text = preg_replace($pat, $rep, trim($text));
- //开源代码phpfensi.com
- return $text;
- }
此函数接受一个url并返回页面的纯文本版本,它使用curl来检索网页,一个正则表达式的组合,以去除所有不必要的空白,这个功能甚至剥夺了从形式和script标记,这是由php函数忽略,如用strip_tags,他们地带唯一的标记文本,留下完整的文字在中间.
正则表达式被分为两个阶段,以避免删除单,也由 s的匹配,回车,但仍然删除所有空白行和多个换行符或空格,修整手术进行了2个阶段进行.