vim 使用正则表达式

港控/mmm° 2022-08-05 12:21 144阅读 0赞

任何一个现代编辑器或编程语言，如果不支持正则表达式，则可考虑立刻放弃，因为正则表达式不仅仅只是高效，还有点身份地位象征的意味。

正则表达式指使用单个字符串来描述、匹配一系列符合某个句法规则的字符串。如果用vi而不懂正则表达式，则等于根本不会用。正则表达式是vi处理文本最有力的武器，稍微上点“档次”的编辑器或语言都支持正则表达式。花点时间学习正则表达式是跟普通程序员拉开距离的捷径。

正则表达式至少可以做到以下事情：

*  文本搜索替换
 *  过滤数据
 *  表单验证
 *  网络爬虫实现

注：正则表达式有很多种实现，各版本之间有些诧异，但基础构成方面都是一样的，学习使用的时候要加以区分。

### 元字符 ###

可理解为关键字或保留字，这些字符做特殊用途

<table style="max-width:100%; border-collapse:collapse; border-spacing:0px; width:619px; margin-bottom:25px; border-top-width:1px; border-right-width:1px; border-bottom-width:1px; border-style:solid solid solid none; border-top-color:rgb(221,221,221); border-right-color:rgb(221,221,221); border-bottom-color:rgb(221,221,221); color:rgb(47,47,47); font-family:'lucida grande','lucida sans unicode',lucida,helvetica,'Hiragino Sans GB','Microsoft YaHei','WenQuanYi Micro Hei',sans-serif; font-size:17px; line-height:30px"> 
 <thead> 
  <tr> 
   <th style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:bottom"> 字符</th> 
   <th style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:bottom"> 解释</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> .</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 匹配换行符以外的任意字符</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> ^</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 匹配字符串的开始位置</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> $</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 匹配字符串的结束位置</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> *</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 匹配前面的子表达式零次或多次，等价于{0,}</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> +</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 匹配前面的子表达式一次或多次，等价于{1,}</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> ?</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 匹配前面的子表达式零次或一次，等价于{0,1}</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> \</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 转义符，将特殊字符进行转义</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> []</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> [abc]字符集合，匹配所包含的任意一个字符</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> &nbsp;</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> [^abc]负值字符集合,匹配未包含的任意字符</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> &nbsp;</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> [a-z] 字符范围，匹配指定范围内的任意字符</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> ()</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 两个字符一起使用，用于创建一个用于匹配的子串，也叫分组</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> {}</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> {n}匹配确定的n次</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> &nbsp;</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> {n,}至少匹配n次，等价于"*"</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> &nbsp;</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> {n,m}最少匹配n次且最多匹配m次（其中n&lt;=m）</td> 
  </tr> 
 </tbody> 
</table>

还有`|` 交替匹配，符号两边的任意一项

### 预设字符 ###

<table style="max-width:100%; border-collapse:collapse; border-spacing:0px; width:619px; margin-bottom:25px; border-top-width:1px; border-right-width:1px; border-bottom-width:1px; border-style:solid solid solid none; border-top-color:rgb(221,221,221); border-right-color:rgb(221,221,221); border-bottom-color:rgb(221,221,221); color:rgb(47,47,47); font-family:'lucida grande','lucida sans unicode',lucida,helvetica,'Hiragino Sans GB','Microsoft YaHei','WenQuanYi Micro Hei',sans-serif; font-size:17px; line-height:30px"> 
 <thead> 
  <tr> 
   <th style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:bottom"> 字符</th> 
   <th style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:bottom"> 解释</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> \b</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 单词边界，同\&lt;</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> \B</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 非单词边界，同 \&gt;</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> \d</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 数字字符，同 [0-9]</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> \D</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 非数字字符，同[^0-9]</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> \s</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 空白字符，同 [ \t\n\r\f\v]</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> \S</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 非空白字符，同 [^\t\n\r\f\v]</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> \w</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 字母数字字符，同 [a-zA-Z0-9_]</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> \W</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 非字母数字字符，同 [^a-zA-Z0-9_]</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> \t</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> Tab，同0x09</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> \r</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 回车符，同0x0D</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> \n</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 换行符，同0x0A</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> \f</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 换页符</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> \v</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 垂直制表符，同ox0b</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> \x</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 十六进制，例如“x41”匹配“A”</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> \u</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> Unicode字符。例如，u00A9匹配版权符号</td> 
  </tr> 
 </tbody> 
</table>

### POSIX字符类 ###

<table style="max-width:100%; border-collapse:collapse; border-spacing:0px; width:619px; margin-bottom:25px; border-top-width:1px; border-right-width:1px; border-bottom-width:1px; border-style:solid solid solid none; border-top-color:rgb(221,221,221); border-right-color:rgb(221,221,221); border-bottom-color:rgb(221,221,221); color:rgb(47,47,47); font-family:'lucida grande','lucida sans unicode',lucida,helvetica,'Hiragino Sans GB','Microsoft YaHei','WenQuanYi Micro Hei',sans-serif; font-size:17px; line-height:30px"> 
 <thead> 
  <tr> 
   <th style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:bottom"> 字符</th> 
   <th style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:bottom"> 解释</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> [:alnum:]</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 匹配任意一个字母或数字字符</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> [:alpha:]</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 匹配任意一个字母字符（包括大小写字母）</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> [:blank:]</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 空格与制表符（横向和纵向）</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> [:digit:]</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 匹配任意一个数字字符</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> [:lower:]</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 匹配小写字母</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> [:upper:]</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 匹配大写字母</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> [:punct:]</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 匹配标点符号</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> [:space:]</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 匹配一个包括换行符、回车等在内的所有空白符</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> [:graph:]</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 匹配任何一个可以看得见的且可以打印的字符</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> [:xdigit:]</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 任何一个十六进制数（即：0-9，a-f，A-F）</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> [:cntrl:]</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 任何一个控制字符（ASCII字符集中的前32个字符)</td> 
  </tr> 
  <tr> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> [:print:]</td> 
   <td style="padding:8px; border-left-width:1px; border-left-style:solid; border-left-color:rgb(221,221,221); border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); line-height:20px; vertical-align:top"> 任何一个可以打印的字符</td> 
  </tr> 
 </tbody> 
</table>

### 常用表达式 ###

#### 数字相关 ####

*  正整数`^[1-9]d*$`
 *  负整数 `^-[1-9]d*$`
 *  整数 `^-?[1-9]d*$`
 *  非负整数（正整数 + 0） `^[1-9]d*|0$`
 *  非正整数（负整数 + 0） `^-[1-9]d*|0$`
 *  正浮点数 `^[1-9]d*.d*|0.d*[1-9]d*$`
 *  负浮点数 `^-([1-9]d*.d*|0.d*[1-9]d*)$`
 *  浮点数 `^-?([1-9]d*.d*|0.d*[1-9]d*|0?.0+|0)$`
 *  非负浮点数（正浮点数 + 0） `^[1-9]d*.d*|0.d*[1-9]d*|0?.0+|0$`
 *  非正浮点数（负浮点数 + 0） `^(-([1-9]d*.d*|0.d*[1-9]d*))|0?.0+|0$`

#### 格式检查 ####

*  匹配中文字符 `[u4e00-u9fa5]`
 *  限定只能输入中文字符：`^[u4e00-u9fa5],{0,}$`
 *  匹配Email地址：`^w+[-+.]w+)*@w+([-.]w+)*.w+([-.]w+)*$`
 *  匹配URL地址：`^http(s)://([w-]+.)+[w-]+(/[w-./?%&=]*)?$`
 *  匹配国内电话号码：`^((d{3,4})|d{3,4}-)?d{7,8}$`
 *  匹配国内邮政编码：`[1-9]d{5}(?!d)`
 *  匹配国内身份证号： `^d{15}|d{18}$`
 *  匹配首尾空白字符 `^s*|s*$`
 *  匹配Email地址 `w+([-+.]w+)*@w+([-.]w+)*.w+([-.]w+)*`
 *  匹配网址URL `[a-zA-z]+://[^s]*`
 *  匹配ip地址：`d+.d+.d+.d+`

#### RegularExpressionValidator表单验证 ####

*  只能输入数字：`^[0-9]*$`
 *  只能输入n位的数字：`^d{n}$`
 *  只能输入至少n位数字：`^d{n,}$`
 *  只能输入m-n位的数字：`^d{m,n}$`
 *  只能输入零和非零开头的数字：`^(0|[1-9][0-9]*)$`
 *  只能输入有两位小数的正实数：`^[0-9]+(.[0-9]{2})?$`
 *  只能输入有1-3位小数的正实数：`^[0-9]+(.[0-9]{1,3})?$`
 *  只能输入非零的正整数：`^+?[1-9][0-9]*$`
 *  只能输入非零的负整数：`^-[1-9][0-9]*$`
 *  只能输入长度为3的字符：`^.{3}$`
 *  只能输入由26个英文字母组成的字符串：`^[A-Za-z]+$`
 *  只能输入由26个大写英文字母组成的字符串：`^[A-Z]+$`
 *  只能输入由26个小写英文字母组成的字符串：`^[a-z]+$`
 *  只能输入由数字和26个英文字母组成的字符串：`^[A-Za-z0-9]+$`
 *  只能输入由数字、26个英文字母或者下划线组成的字符串：`^w+$`
 *  匹配帐号是否合法(字母开头，允许5-16字节，允许字母数字下划线)：`^[a-zA-Z][a-zA-Z0-9_]{4,15}$`
 *  验证月数：`^(0?[1-9]|1[0-2])$`正确格式为：“01”-“09”和“1”“12”
 *  验证天数：`^((0?[1-9])|((1|2)[0-9])|30|31)$`

### 在vim中使用正则表达式 ###

基本表达式: `[range]s/from/to/[flags]`

*  range:搜索范围，如果没有指定范围，则作用于但前行。

:1,10s/from/to/ 表示在第1到第10行（包含第1，第10行）之间搜索替换；
    :10s/from/to/ 表示只在第10行搜索替换；
    :%s/from/to/ 表示在所有行中搜索替换；
    :1,$s/from/to/ 同上。

*  flags 有如下四个选项

c confirm，每次替换前询问；
    e error， 不显示错误；
    g globle，不询问，整行替换。如果不加g选项，则只替换每行的第一个匹配到的字符串；
    i ignore，忽略大小写。

#### 例子 ####

1.  将foo(a,b,c) 改为foo(b,a,c)  
    `:%s/foo($[^,]*$,$[^,]*$,$[^)]*$)/foo(\2,\1,\3)/g`
2.  将abcdef abcedg 都替换为 abc asd  
    `:%s/abc.*/abc asd/g`
3.  删除以数字开头的行  
    `%s/^\d.*$//g`
4.  删除以\[a,b,c\]开头的行  
    `:%s/^[a|b|c].*$//g`
5.  替换windows换行符  
    `:%s/<c-v><c-m>//g`
6.  将url替换为html链接  
    `:s/$http:\/\/[-a-z\._~\+%\/]\+$/<a href="\1">\1<\/a>/`
7.  将各行的 id 字符串替换为行号  
    id 123  
    id 456  
    `:%s/\<id\>/\=line(".")`
8.  将多个空格替换为1个  
    `:%s/ */ /g`
9.  删除行尾空格  
    `:%s/ *$//g`
10. 删除行首空格  
    `:%s/^ *//g`
11. 删除所有空白行  
    `:g/^\s*$/d`
12. 删除所有出现有string的行  
    `:g/string/d`
13. 删除所有不包含string的行  
    `:v/string/d`
14. 删除所有HTMl标签，保留文本  
    `:%s#<{FNXX==XXFN}\+>##g`
15. 删除重复行  
    `:%s/^$.*$\n\1$/\1/g`
16. 每行开头加一个空格  
    `:%s/^/ /g`
17. 修改错误拼写，例如文本中出现了beg,bssg,big都替换成bug  
    `:%s/b[e|s|i].*g/bug/g`
18. 批量添加注释  
    `:%s/^/#/`每行开头添加\#号  
    `:3,10s/^/#/` 3-10行每行开头添加\#号