对于开发人员来说，正则表达式是一个非常有用的功能，它提供了 查找，匹配，替换 句子，单词，或者其他格式的字符串。这篇文章主要介绍了15个超实用的php正则表达式，需要的朋友可以参考下。在这篇文章里，我已经编写了15个超有用 的正则表达式，web开发人员都应该将它收藏到自己的工具包。
验证域名检验一个字符串是否是个有效域名
<ol class="dp-j"><li class="alt"><span><span>$url = </span><span class="string">"http://komunitasweb.com/"</span><span>; </span></span></li><li><span><span class="keyword">if</span><span> (preg_match(</span><span class="string">'/^(http|https|ftp)://([A-Z0-9][A-Z0-9_-]*(?:.[A-Z0-9][A-Z0-9_-]*)+):?(d+)?/?/i'</span><span>, $url)) { </span></span></li><li class="alt"><span> echo <span class="string">"Your url is ok."</span><span>; </span></span></li><li><span>} <span class="keyword">else</span><span> { </span></span></li><li class="alt"><span> echo <span class="string">"Wrong url."</span><span>; </span></span></li><li><span>} </span></li></ol>从一个字符串中 突出某个单词
这是一个非常有用的在一个字符串中匹配出某个单词 并且突出它，非常有效的搜索结果
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<ol class="dp-j"><li class="alt"><span><span>$text = "Sample sentence from KomunitasWeb, regex has become popular in web programming. Now we learn regex. According to wikipedia, Regular expressions (abbreviated as regex or </span></span></li><li><span> </span></li><li class="alt"><span>regexp, with plural forms regexes, regexps, or regexen) are written in a formal language that can be interpreted by a regular expression processor"; </span></li><li><span>$text = preg_replace(<span class="string">"/b(regex)b/i"</span><span>, </span><span class="string">'<span style="background:#5fc9f6">1</span>'</span><span>, $text); </span></span></li><li class="alt"><span>echo $text; </span></li></ol>
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突出查询结果在你的 WordPress 博客里就像刚才我说的，上面的那段代码可以很方便的搜索出结果，而这里是一个更好的方式去执行搜索在某个WordPress的博客上打开你的文件 search.php ，然后找到 方法 the_title() 然后用下面代码替换掉它
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<ol class="dp-j"><li class="alt"><span><span>echo $title; </span></span></li><li><span> </span></li><li class="alt"><span>Now, just before the modified line, add <span class="keyword">this</span><span> code: </span></span></li><li><span> </span></li><li class="alt"><span><php </span></li><li><span> $title = get_the_title(); </span></li><li class="alt"><span> $keys= explode(<span class="string">" "</span><span>,$s); </span></span></li><li><span> $title = preg_replace(<span class="string">'/('</span><span>.implode(</span><span class="string">'|'</span><span>, $keys) .</span><span class="string">')/iu'</span><span>, </span></span></li><li class="alt"><span> <span class="string">'<strong> </strong>'</span><span>, </span></span></li><li><span> $title); </span></li><li class="alt"><span>> </span></li><li><span> </span></li><li class="alt"><span>Save the search.php file and open style.css. Append the following line to it: </span></li><li><span> </span></li><li class="alt"><span>strong.search-excerpt { background: yellow; } <br /></span></li></ol>从HTML文档中获得全部图片
如果你曾经希望去获得某个网页上的全部图片，这段代码就是你需要的，你可以轻松的建立一个图片下载机器人
<ol class="dp-j"><li class="alt"><span><span>$images = array(); </span></span></li><li><span>preg_match_all(<span class="string">'/(img|src)=("|'</span><span>)[^"</span><span class="string">'>]+/i'</span><span>, $data, $media); </span></span></li><li class="alt"><span>unset($data); </span></li><li><span>$data=preg_replace(<span class="string">'/(img|src)("|'</span><span>|="|=</span><span class="string">')(.*)/i'</span><span>,</span><span class="string">"$3"</span><span>,$media[</span><span class="number">0</span><span>]); </span></span></li><li class="alt"><span>foreach($data as $url) </span></li><li><span>{ </span></li><li class="alt"><span> $info = pathinfo($url); </span></li><li><span> <span class="keyword">if</span><span> (isset($info[</span><span class="string">'extension'</span><span>])) </span></span></li><li class="alt"><span> { </span></li><li><span> <span class="keyword">if</span><span> (($info[</span><span class="string">'extension'</span><span>] == </span><span class="string">'jpg'</span><span>) || </span></span></li><li class="alt"><span> ($info[<span class="string">'extension'</span><span>] == </span><span class="string">'jpeg'</span><span>) || </span></span></li><li><span> ($info[<span class="string">'extension'</span><span>] == </span><span class="string">'gif'</span><span>) || </span></span></li><li class="alt"><span> ($info[<span class="string">'extension'</span><span>] == </span><span class="string">'png'</span><span>)) </span></span></li><li><span> array_push($images, $url); </span></li><li class="alt"><span> } </span></li><li><span>} </span></li></ol>删除重复字母
经常重复输入字母? 这个表达式正适合.
<ol class="dp-j"><li class="alt"><span><span>$text = preg_replace(</span><span class="string">"/s(w+s)1/i"</span><span>, </span><span class="string">"$1"</span><span>, $text); </span></span></li></ol>
删除重复的标点
功能同上，但只是面对标点，白白重复的逗号
<ol class="dp-j"><li class="alt"><span><span>$text = preg_replace(</span><span class="string">"/.+/i"</span><span>, </span><span class="string">"."</span><span>, $text); </span></span></li></ol>
匹配一个XML或者HTML标签
这个简单的函数有两个参数：第一个是你要匹配的标签，第二个是包含XML或HTML的变量，再强调下，这个真的很强大
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<ol class="dp-j"><li class="alt"><span><span>function get_tag( $tag, $xml ) { </span></span></li><li><span>$tag = preg_quote($tag); </span></li><li class="alt"><span>preg_match_all(<span class="string">'{<'</span><span>.$tag.</span><span class="string">'[^>]*>(.*?)</'</span><span>.$tag.</span><span class="string">'>.'</span><span>}', </span></span></li><li><span> $xml, </span></li><li class="alt"><span> $matches, </span></li><li><span> PREG_PATTERN_ORDER); </span></li><li class="alt"><span> </span></li><li><span><span class="keyword">return</span><span> $matches[</span><span class="number">1</span><span>]; </span></span></li><li class="alt"><span>} </span></li></ol>匹配具有属性值的XML或者HTML标签
这个功能和上面的非常相似，但是它允许你匹配的标签内部有属性值，例如你可以轻松匹配
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<ol class="dp-j"><li class="alt"><span><span>function get_tag( $attr, $value, $xml, $tag=</span><span class="keyword">null</span><span> ) { </span></span></li><li><span><span class="keyword">if</span><span>( is_null($tag) ) </span></span></li><li class="alt"><span> $tag = <span class="string">'w+'</span><span>; </span></span></li><li><span><span class="keyword">else</span><span> </span></span></li><li class="alt"><span> $tag = preg_quote($tag); </span></li><li><span> </span></li><li class="alt"><span>$attr = preg_quote($attr); </span></li><li><span>$value = preg_quote($value); </span></li><li class="alt"><span> </span></li><li><span>$tag_regex = <span class="string">"/<("</span><span>.$tag.</span><span class="string">")[^>]*$attrs*=s*"</span><span>. </span></span></li><li class="alt"><span> <span class="string">"(['"])$value\2[^>]*>(.*?)</\1>/"</span><span> </span></span></li><li><span> </span></li><li class="alt"><span>preg_match_all($tag_regex, </span></li><li><span> $xml, </span></li><li class="alt"><span> $matches, </span></li><li><span> PREG_PATTERN_ORDER); </span></li><li class="alt"><span> </span></li><li><span><span class="keyword">return</span><span> $matches[</span><span class="number">3</span><span>]; </span></span></li><li class="alt"><span>} </span></li></ol>匹配十六进制颜色值
web开发者的另一个有趣的工具，它允许你匹配和验证十六进制颜色值.
<ol class="dp-j"><li class="alt"><span><span>$string = </span><span class="string">"#555555"</span><span>; </span></span></li><li><span><span class="keyword">if</span><span> (preg_match(</span><span class="string">'/^#(?:(?:[a-fd]{3}){1,2})$/i'</span><span>, $string)) { </span></span></li><li class="alt"><span>echo <span class="string">"example 6 successful."</span><span>; </span></span></li><li><span>} </span></li></ol>查找页面 title
这段代码方便查找和打印 网页
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<ol class="dp-j"><li class="alt"><span><span>$fp = fopen(</span><span class="string">"http://www.catswhocode.com/blog"</span><span>,</span><span class="string">"r"</span><span>); </span></span></li><li><span><span class="keyword">while</span><span> (!feof($fp) ){ </span></span></li><li class="alt"><span> $page .= fgets($fp, <span class="number">4096</span><span>); </span></span></li><li><span>} </span></li><li class="alt"><span> </span></li><li><span>$titre = eregi(<span class="string">"<title>(.*)</title>"</span><span>,$page,$regs); </span></span></li><li class="alt"><span>echo $regs[<span class="number">1</span><span>]; </span></span></li><li><span>fclose($fp); </span></li></ol>解释 Apache 日志
大多数网站使用的都是著名的Apache服务器，如果你的网站也是，那么使用PHP正则表达式解析 apache 服务器日志 怎么样？
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<ol class="dp-j"><li class="alt"><span><span class="comment">//Logs: Apache web server</span><span> </span></span></li><li><span><span class="comment">//Successful hits to HTML files only. Useful for counting the number of page views.</span><span> </span></span></li><li class="alt"><span><span class="string">'^((?#client IP or domain name)S+)s+((?#basic authentication)S+s+S+)s+[((?#date and time)[^]]+)]s+"(?:GET|POST|HEAD) ((?#file)/[^ ?"]+?.html?)??((?#parameters)[^ ?"]+)? HTTP/[0-9.]+"s+(?#status code)200s+((?#bytes transferred)[-0-9]+)s+"((?#referrer)[^"]*)"s+"((?#user agent)[^"]*)"$'</span><span> </span></span></li><li><span> </span></li><li class="alt"><span><span class="comment">//Logs: Apache web server</span><span> </span></span></li><li><span><span class="comment">//404 errors only</span><span> </span></span></li><li class="alt"><span><span class="string">'^((?#client IP or domain name)S+)s+((?#basic authentication)S+s+S+)s+[((?#date and time)[^]]+)]s+"(?:GET|POST|HEAD) ((?#file)[^ ?"]+)??((?#parameters)[^ ?"]+)? HTTP/[0-9.]+"s+(?#status code)404s+((?#bytes transferred)[-0-9]+)s+"((?#referrer)[^"]*)"s+"((?#user agent)[^"]*)"$'</span><span> </span></span></li></ol>
使用智能引号代替双引号
如果你是一个印刷爱好者，你将喜欢这个允许用智能引号代替双引号的正则表达式，这个正则被WORDPRESS在其内容上使用
<ol class="dp-j"><li class="alt"><span><span>preg_replace(</span><span class="string">'B"b([^"x84x93x94rn]+)b"B'</span><span>, </span><span class="string">'?1?'</span><span>, $text); </span></span></li></ol>
检验密码的复杂度
这个正则表达式将检测输入的内容是否包含6个或更多字母，数字，下划线和连字符. 输入必须包含至少一个大写字母，一个小写字母和一个数字
'A(?=[-_a-zA-Z0-9]*?[A-Z])(?=[-_a-zA-Z0-9]*?[a-z])(?=[-_a-zA-Z0-9]*?[0-9])[-_a-zA-Z0-9]{6,}z'
WordPress: 使用正则获得帖子上的图片
我知道很多人是WORDPRESS的使用者，你可能会喜欢并且愿意使用 那些从帖子的内容检索下来的图像代码。使用这个代码在你的BLOG只需要复制下面代码到你的某个文件里
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<ol class="dp-j"><li class="alt"><span><span><php </span><span class="keyword">if</span><span> (have_posts()) : ?> </span></span></li><li><span><php <span class="keyword">while</span><span> (have_posts()) : the_post(); ?> </span></span></li><li class="alt"><span> </span></li><li><span><php </span></li><li class="alt"><span>$szPostContent = $post->post_content; </span></li><li><span>$szSearchPattern = <span class="string">'~@@##@@]* />~'</span><span>; </span></span></li><li class="alt"><span> </span></li><li><span><span class="comment">// Run preg_match_all to grab all the images and save the results in $aPics</span><span> </span></span></li><li class="alt"><span>preg_match_all( $szSearchPattern, $szPostContent, $aPics ); </span></li><li><span> </span></li><li class="alt"><span><span class="comment">// Check to see if we have at least 1 image</span><span> </span></span></li><li><span>$iNumberOfPics = count($aPics[<span class="number">0</span><span>]); </span></span></li><li class="alt"><span> </span></li><li><span><span class="keyword">if</span><span> ( $iNumberOfPics > </span><span class="number">0</span><span> ) { </span></span></li><li class="alt"><span> <span class="comment">// Now here you would do whatever you need to do with the images</span><span> </span></span></li><li><span> <span class="comment">// For this example the images are just displayed</span><span> </span></span></li><li class="alt"><span> <span class="keyword">for</span><span> ( $i=</span><span class="number">0</span><span>; $i < $iNumberOfPics ; $i++ ) { </span></span></li><li><span> echo $aPics[<span class="number">0</span><span>][$i]; </span></span></li><li class="alt"><span> }; </span></li><li><span>}; </span></li><li class="alt"><span> </span></li><li><span>endwhile; </span></li><li class="alt"><span>endif; </span></li><li><span>> </span></li></ol>自动生成笑脸图案
被WordPress使用的另一个方法, 这段代码可使你把图像自动更换一个笑脸符号
<ol class="dp-j"><li class="alt"><span><span>$texte=</span><span class="string">'A text with a smiley '</span><span>; </span></span></li><li><span>echo str_replace(<span class="string">':-)'</span><span>,</span><span class="string">'@@##@@'</span><span>,$texte); </span></span></li></ol>
移除图片的链接
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<ol class="dp-j"><li class="alt"><span><span><meta http-equiv=</span><span class="string">"Content-Type"</span><span> content=</span><span class="string">"text/html; charset=utf-8"</span><span> /> </span></span></li><li><span><php </span></li><li class="alt"><span> $str = ' </span></li><li><span> <a href=<span class="string">"http://www.jobbole.com/"</span><span>>jobbole</a>其他字符 </span></span></li><li class="alt"><span> <a href=<span class="string">"http://www.sohu.com/"</span><span>>sohu</a> </span></span></li><li><span> <a href=<span class="string">"http://www.sohu.com/"</span><span>>@@##@@<span class="string">"http://www.fashion-press.net/img/news/3176/mot_06.jpg"</span><span> /></a> </span></span></li><li class="alt"><span> <br>'; </span></li><li><span> </span></li><li class="alt"><span> <span class="comment">//echo preg_replace("/(<a.*?>)(@@##@@)(</a>)/", '$2', $str); </span><span> </span></span></li><li><span> echo preg_replace(<span class="string">"/(<a.*?>)(@@##@@)(</a>)/"</span><span>, </span><span class="string">''</span><span>, $str); </span></span></li><li class="alt"><span>> </span></li></ol>以上就是15个超实用的php正则表达式，希望对大家的学习有所帮助。
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