# 第八課 正則表達式
> 常用正則
```
<pre class="calibre14">```
<span class="token2">(</span><span class="token2">[</span>\s\S<span class="token2">]</span><span class="token">*</span><span class="token">?</span><span class="token2">)</span> 表示任意多個字符<span class="token2">,</span>換行也可以匹配
<span class="token2">(</span><span class="token2">[</span>\s<span class="token">*</span><span class="token2">]</span><span class="token">+</span><span class="token2">)</span> 匹配一個或多個空格
<span class="token2">(</span><span class="token2">[</span>\s<span class="token2">,</span><span class="token2">]</span><span class="token">+</span><span class="token2">)</span> 匹配多個空格或逗號
<span class="token2">(</span><span class="token2">[</span><span class="token2">,</span><span class="token2">]</span><span class="token">+</span><span class="token2">)</span> 匹配多個逗號
<span class="token">/</span>php<span class="token">/</span>i 不區分大小寫
<span class="token">^</span> $ 匹配開始結束字符
<span class="token2">.</span> 匹配除換行以外字符串
<span class="token">?</span> <span class="token3">0</span>次 或 <span class="token3">1</span>次 等價<span class="token2">{</span><span class="token3">0</span><span class="token2">,</span><span class="token3">1</span><span class="token2">}</span>
<span class="token">*</span> <span class="token3">0</span>次 或 多次 等價<span class="token2">{</span><span class="token3">0</span><span class="token2">,</span><span class="token2">}</span>
<span class="token">+</span> <span class="token3">1</span>次 或 多次 等價<span class="token2">{</span><span class="token3">1</span><span class="token2">,</span><span class="token2">}</span>
<span class="token">-</span> 表示范圍
<span class="token2">[</span><span class="token2">]</span> 開始結束字符類定義
\d 任意<span class="token3">10</span>進制數字 <span class="token2">[</span><span class="token3">0</span><span class="token">-</span><span class="token3">9</span><span class="token2">]</span>
\s 任意空白字符 單個
\S 任意非空白字符
\w 任意單詞字符 等價<span class="token2">[</span>a<span class="token">-</span>zA<span class="token">-</span>Z0<span class="token">-</span><span class="token3">9</span><span class="token2">]</span>
<span class="token2">(</span><span class="token">?</span><span class="token2">:</span>中國<span class="token">|</span>美國<span class="token2">)</span><span class="token2">(</span><span class="token2">.</span><span class="token">*</span><span class="token2">)</span> 匹配中國<span class="token2">,</span>美國開頭的字符串
<span class="token2">(</span>\d<span class="token">+</span>\<span class="token2">.</span>\d<span class="token">+</span>\<span class="token2">.</span>\d<span class="token">+</span>\<span class="token2">.</span>\d<span class="token">+</span><span class="token2">)</span> IP
<span class="token2">(</span><span class="token2">[</span>a<span class="token">-</span>zA<span class="token">-</span>Z<span class="token2">]</span><span class="token2">[</span>a<span class="token">-</span>zA<span class="token">-</span>Z0<span class="token">-</span><span class="token3">9</span>_<span class="token2">]</span><span class="token2">)</span> 匹配是否合法字母開頭
<span class="token2">(</span>\d<span class="token">-</span>\d<span class="token">|</span>\d<span class="token">-</span>\d<span class="token2">)</span> 電話號碼
<span class="token2">[</span><span class="token3">1</span><span class="token">-</span><span class="token3">9</span><span class="token2">]</span><span class="token2">[</span><span class="token3">0</span><span class="token">-</span><span class="token3">9</span><span class="token2">]</span> qq
<span class="token">^</span><span class="token2">[</span>\w\<span class="token2">.</span>\<span class="token">-</span><span class="token2">]</span><span class="token">+</span>@\w<span class="token">+</span><span class="token2">(</span><span class="token2">[</span>\<span class="token2">.</span>\<span class="token">-</span><span class="token2">]</span>\w<span class="token">+</span><span class="token2">)</span><span class="token">*</span>\<span class="token2">.</span>\w<span class="token">+</span>$ email
href<span class="token">=</span><span class="token4">"(.*?)"</span> 超鏈接
<span class="token">/</span><span class="token">^</span>\d<span class="token2">{</span><span class="token3">1</span><span class="token2">,</span><span class="token3">6</span><span class="token2">}</span>$<span class="token">/</span> 匹配<span class="token3">0</span><span class="token">-</span><span class="token3">999999</span>
<span class="token">/</span>\d<span class="token2">{</span><span class="token3">4</span><span class="token2">}</span>年\d<span class="token2">{</span><span class="token3">1</span><span class="token2">,</span><span class="token3">2</span><span class="token2">}</span>月\d<span class="token2">{</span><span class="token3">1</span><span class="token2">,</span><span class="token3">2</span><span class="token2">}</span><span class="token">/</span> 匹配年月日
```
```
> preg\_math 匹配一次,成功返回 true
```
<pre class="calibre14">```
<span class="token1">preg_match</span><span class="token2">(</span><span class="token4">"/\<center>([\s\S]*?)<\/center\>/"</span><span class="token2">,</span>$str<span class="token2">,</span>$rs<span class="token2">)</span><span class="token2">;</span>
```
```
> preg\_match\_all匹配多次,成功返回true
```
<pre class="calibre14">```
<span class="token1">preg_match_all</span><span class="token2">(</span><span class="token4">"/\<center>([\s\S]*?)<\/center\>/"</span><span class="token2">,</span>$str<span class="token2">,</span>$rs<span class="token2">)</span><span class="token2">;</span>
```
```
> preg\_replace 匹配替換,替換成$re
```
<pre class="calibre14">```
$rs <span class="token">=</span><span class="token1">preg_replace</span><span class="token2">(</span><span class="token4">"/\<center>([\s\S]*?)<\/center\>/"</span><span class="token2">,</span>$re<span class="token2">,</span>$str<span class="token2">)</span><span class="token2">;</span>
```
```
> preg\_split分割成數組
```
<pre class="calibre14">```
$arr <span class="token">=</span> <span class="token1">preg_split</span><span class="token2">(</span><span class="token4">'/([\s*]+)/'</span><span class="token2">,</span><span class="token4">"a b c d ef"</span><span class="token2">)</span><span class="token2">;</span>
```
```
替換
```
<pre class="calibre14">```
$str <span class="token">=</span> <span class="token4">"選項[http://127.0.0.1/weixin/addons/yoby_diyform/weui/fm.jpg]你好"</span><span class="token2">;</span>
$str1 <span class="token">=</span> <span class="token1">preg_replace</span><span class="token2">(</span><span class="token4">"/(?:\[)(.*?)(?:\])/i"</span><span class="token2">,</span> <span class="token4">"<img src=\"\${1}\" />"</span><span class="token2">,</span> $str<span class="token2">)</span><span class="token2">;</span>
<span class="token1">preg_replace</span><span class="token2">(</span><span class="token4">"/.*\|(.*?)\|.*/i"</span><span class="token2">,</span> <span class="token4">"\${1}"</span><span class="token2">,</span> $v<span class="token2">)</span><span class="token2">;</span> 字符<span class="token">|</span><span class="token3">120000</span><span class="token">|</span>來了 輸出<span class="token3">120000</span>
```
```
\\s+ 多個空白
\[^>\] >左邊任意字符
.\*? 任意多個字符
\\d+ 匹配數字
```
<pre class="calibre14">```
<span class="token6">/*獲取html并用正則處理*/</span>
<span class="token5">function</span> <span class="token1">get_content</span><span class="token2">(</span>$url<span class="token2">)</span><span class="token2">{</span>
$html <span class="token">=</span> <span class="token1">file_get_contents</span><span class="token2">(</span>$url<span class="token2">)</span><span class="token2">;</span>
$code<span class="token">=</span> <span class="token1">mb_detect_encoding</span><span class="token2">(</span>$html<span class="token2">,</span> <span class="token1">array</span><span class="token2">(</span><span class="token4">"GB2312"</span><span class="token2">,</span><span class="token4">"GBK"</span><span class="token2">,</span><span class="token4">'UTF-8'</span><span class="token2">,</span><span class="token4">'BIG5'</span><span class="token2">)</span><span class="token2">)</span><span class="token2">;</span><span class="token6">//獲取編碼</span>
<span class="token5">if</span><span class="token2">(</span>$code<span class="token">!=</span><span class="token4">"UTF-8"</span><span class="token2">)</span><span class="token2">{</span>
$htmls <span class="token">=</span> <span class="token1">mb_convert_encoding</span><span class="token2">(</span>$html<span class="token2">,</span> <span class="token4">"UTF-8"</span><span class="token2">,</span> $code<span class="token2">)</span><span class="token2">;</span><span class="token6">//轉換內容為UTF-8編碼</span>
<span class="token2">}</span><span class="token5">else</span><span class="token2">{</span>
$htmls <span class="token">=</span> $html<span class="token2">;</span>
<span class="token2">}</span>
$htmls <span class="token">=</span> <span class="token1">preg_replace</span><span class="token2">(</span><span class="token4">"/<script[\s\S]*?<\/script>/i"</span><span class="token2">,</span><span class="token4">""</span><span class="token2">,</span>$htmls<span class="token2">,</span><span class="token">-</span><span class="token3">1</span><span class="token2">)</span><span class="token2">;</span><span class="token6">//去除script</span>
$htmls <span class="token">=</span> <span class="token1">preg_replace</span><span class="token2">(</span><span class="token4">"/<noscript[\s\S]*?<\/noscript>/i"</span><span class="token2">,</span><span class="token4">""</span><span class="token2">,</span>$htmls<span class="token2">,</span><span class="token">-</span><span class="token3">1</span><span class="token2">)</span><span class="token2">;</span><span class="token6">//去除noscript</span>
$htmls<span class="token">=</span><span class="token1">preg_replace</span><span class="token2">(</span><span class="token4">"/<(\/?link.*?)>/si"</span><span class="token2">,</span><span class="token4">""</span><span class="token2">,</span>$htmls<span class="token2">)</span><span class="token2">;</span><span class="token6">//去掉link</span>
$htmls<span class="token">=</span><span class="token1">preg_replace</span><span class="token2">(</span><span class="token4">"/<(style.*?)>(.*?)<(\/style.*?)>/si"</span><span class="token2">,</span><span class="token4">""</span><span class="token2">,</span>$htmls<span class="token2">)</span><span class="token2">;</span><span class="token6">//去掉style</span>
$htmls <span class="token">=</span><span class="token1">preg_replace</span><span class="token2">(</span><span class="token4">"/style=.+?['|\"]/i"</span><span class="token2">,</span><span class="token4">''</span><span class="token2">,</span>$htmls<span class="token2">,</span><span class="token">-</span><span class="token3">1</span><span class="token2">)</span><span class="token2">;</span><span class="token6">//去除style行內樣式</span>
$htmls <span class="token">=</span><span class="token1">preg_replace</span><span class="token2">(</span><span class="token4">'#<!--[^\!\[]*?(?<!\/\/)-->#'</span> <span class="token2">,</span> <span class="token4">''</span> <span class="token2">,</span> $htmls<span class="token2">)</span><span class="token2">;</span><span class="token6">//去掉html注釋</span>
$htmls <span class="token">=</span> <span class="token1">preg_replace</span><span class="token2">(</span><span class="token4">"/<a[^>]*>(.*?)<\/a>/is"</span><span class="token2">,</span> <span class="token4">"$1"</span><span class="token2">,</span> $htmls<span class="token2">)</span><span class="token2">;</span><span class="token6">//去除外站超鏈接</span>
$htmls <span class="token">=</span> <span class="token1">preg_replace</span><span class="token2">(</span><span class="token4">"/(\n\r)/i"</span><span class="token2">,</span> <span class="token4">''</span><span class="token2">,</span> $htmls<span class="token2">)</span><span class="token2">;</span> <span class="token6">//去掉空行</span>
<span class="token5">return</span> $htmls<span class="token2">;</span>
<span class="token2">}</span>
<span class="token1">preg_match</span><span class="token2">(</span><span class="token4">'/<div class="infoBox-list".*?>.*?<div class="news-page clearfix">/ism'</span><span class="token2">,</span> $htmls<span class="token2">,</span> $rs<span class="token2">)</span><span class="token2">;</span>
$htmls <span class="token">=</span> $rs<span class="token2">[</span><span class="token3">0</span><span class="token2">]</span><span class="token2">;</span><span class="token6">//獲取兩個class之間內容</span>
$url <span class="token">=</span> <span class="token2">(</span><span class="token1">preg_match</span><span class="token2">(</span><span class="token4">'/^http(s)?:\\/\\/.+/'</span><span class="token2">,</span>$url<span class="token2">)</span><span class="token2">)</span><span class="token">?</span>$url<span class="token2">:</span>"http<span class="token2">:</span><span class="token">/</span><span class="token">/</span>
"<span class="token2">.</span>$url<span class="token2">;</span><span class="token6">//判斷是否包含https/http</span>
<span class="token1">preg_match</span><span class="token2">(</span><span class="token4">"/src=\"\/?(.*?)\"/"</span><span class="token2">,</span>$content<span class="token2">,</span>$match<span class="token2">)</span><span class="token2">;</span>
第一張圖片
```
```
```
<pre class="calibre16">```
<span class="token2">[</span>\u4e00<span class="token">-</span>\u9fa5<span class="token2">]</span><span class="token2">{</span><span class="token3">0</span><span class="token2">,</span><span class="token2">}</span> 匹配中文
\d<span class="token">+</span> 匹配<span class="token">>=</span><span class="token3">0</span>數字
<span class="token2">[</span>a<span class="token">-</span>zA<span class="token">-</span>Z<span class="token2">]</span><span class="token">+</span> 不區分大小寫<span class="token3">26</span>個字母
<span class="token2">[</span>A<span class="token">-</span>Za<span class="token">-</span>z0<span class="token">-</span><span class="token3">9</span><span class="token2">]</span><span class="token">+</span> 英文與數字
\s<span class="token">+</span> 多個空格
<span class="token2">[</span><span class="token3">0</span><span class="token">-</span><span class="token3">9</span><span class="token2">]</span><span class="token">*</span> 匹配一串數字
\d<span class="token2">{</span><span class="token3">4</span><span class="token2">}</span> 匹配四位數字
\d<span class="token2">{</span><span class="token3">5</span><span class="token2">,</span><span class="token2">}</span> 匹配至少<span class="token3">5</span>位數
\d<span class="token2">{</span><span class="token3">4</span><span class="token2">,</span><span class="token3">10</span><span class="token2">}</span> 匹配<span class="token3">4</span><span class="token">-</span><span class="token3">10</span>位數
```
```
- 簡介
- 第一章 數據庫
- Mysql/mariadb
- 函數
- 基礎
- 增刪改索引
- 標準查詢
- 高級查詢
- TIDB集群mysql解決方案
- Redis
- 語言基礎
- 5種數據類型
- 其他類型
- Sqlite
- 語言基礎
- 常用查詢
- 第二章 PHP
- 語言基礎
- 第一課 流程控制和運算
- 第二課 數組
- 第三課 日期時間
- 第四課 常用函數
- 第五課 字符串
- 第六課 文件操作
- 第七課 面向對象
- 第八課 正則表達式
- 第九課 圖片處理生成
- 第十課 curl/memche
- 第十一課 mysql和pdo
- 第十三課 cookie和session
- 第十四課 xml操作
- 第十五課 php5.3+新特性
- 第十六課 php7+
- 第十七課 密碼安全
- 廢棄函數
- php命令行
- redis應用
- 算法
- 排序算法
- 基礎算法
- 無限級分類
- 自定義函數Fn
- 查找算法
- 自定義函數數據函數fn
- laravel
- 路由
- 常用語句
- 數據庫
- dingo/api
- Yii2
- 控制器
- 常用類
- 數據庫
- redis
- thinkphp6
- TP6文檔
- TP6插件
- dedecms
- 織夢標簽大全
- 數據庫操作
- 內置函數和定義函數
- 織夢核心改動
- 織夢插件/底層標簽開發
- PHP相關工具
- composer
- php開發環境phpenv
- Phpstorm使用
- windows編譯php擴展
- PHP開源庫
- 開源項目管理禪道
- sns_auth
- php-casbin權限控制
- php-jwt
- 微信SDKeasywechat
- querylist采集庫
- workerman
- Box/Spout處理excel和csv
- dll擴展
- redis/memche/xdebug
- redis
- Lua
- php_xlswriter
- event
- swoole
- 常用代碼庫
- 微擎框架
- 第一課全局變量
- 第二課常用函數
- 第三課自定義微擎獨有函數
- 第四課數據庫操作
- 第五課微信端回復
- 第六課微擎高級操作
- 第八課global函數列表
- mainfest.xml詳解
- js方法
- 人人商城
- 第一課model解讀
- 第二課常用語句解讀
- 第三課常用js解讀
- 第四課附錄常見問題
- 第五課附錄處理報表|支付
- 常用JSON狀態碼
- 第三章 JavaScript
- js基礎
- 瀏覽器對象
- 語言基礎
- html5接口
- ES6新語法
- vue
- 基礎語法
- 京東vueUI組件
- uniapp
- 組件開發規范
- nodejs
- 基礎知識
- 安裝node
- nvm不同版本node切換
- js常用標準庫
- zepto/jquery
- weui
- js圖標庫
- elementUI
- validator表單驗證
- layer彈出層
- requirejs
- wow動畫
- 動畫animate
- swiper4
- 百度編輯器
- flyio/axios/qs
- jquery.form
- bootstrap3
- clipboard復制
- slideout側滑
- imagehover.css圖片懸停動畫
- webpack打包
- Bulma UI框架
- store 客戶端存儲
- lottie動畫創建庫
- sweetalert
- js自定義函數
- 常見JSSDK
- 微信公眾號JSSDK
- 騰訊地圖jssdk
- 微信小程序
- 第四章 編程語言
- markdown語言
- Dart語言
- Dart語言基礎
- Flutter框架
- Lua語言
- 字符串,數組,表
- 自定義方法
- go語言
- 第1.1語言基本語法
- 第1.2流程控制
- 第1.3函數
- 第1.4結構體
- 第1.5接口
- 第1.6包
- go語言框架Gin
- CSS3語言
- CSS與CSS3
- 選擇符
- 屬性
- css3
- loading動畫
- HTML5語言
- less
- sass
- C#
- 基礎知識
- 函數
- 第五章 開發工具
- git
- nginx/apache服務器
- Linux常用操作
- crontab定時任務
- 注冊表與cmd
- 阿里云ECS
- frp穿透和ssl續期
- 寶塔安裝
- 樹莓派
- 瀏覽器模擬
- 火狐/chrome常用插件
- WSL安裝使用
- mac brew和終端命令
- win10相關