正则表达式可视化工具

IP地址

  IP 地址由 4 个字节构成（这 4 The value range of each byte is both 0~255）.IP The address is usually written as 4 组以 . character-separated integers（每个整数由 1~3 位数字构成）.
【文本】
localhost is 127.0.0.1
【正则表达式】

(((\d{
    1,2})|(1\d{
    2})|(2[0-4]\d)|(25[0-5]))\.){
    3}((\d{
    1,2})|(1\d{
    2})|(2[0-4]\d)|(25[0-5]))

【结果】
localhost is 127.0.0.1
【分析】
  The pattern uses a series of nested subexpressions.( ( ( \d{1, 2} ) | ( 1 \d{2}) | ( 2 [0-4] \d) | (25 [0-5]) ) .) 由 4 consists of nested subexpressions：( \d{1, 2} ) 匹配任意 1 位或 2 位数字 ( 0~99 ),( 1 \d{2}) 匹配以 1 开头的任意 3 位数字 ( 100~1999),( 2 [0-4] \d) 匹配整数 200~249;(25 [0-5]) 匹配整数 250~255.这 4 部分通过 | 操作符（The implication is that only part of it needs to be matched）forms a subexpression.随后的 . 用来匹配 . 字符,It forms a larger subexpression with the previous one,接下来的 { 3 } Indicates that repetition is required 3 次.最后,The range of values ​​appears again 1 次（This time the tail is omitted . ）,to match the last set of numbers.通过把 4 Group numbers are all limited to 0 到 255 之间,This pattern does exactly that and only matches valid ones IP 地址,Exclude invalid ones IP 地址.

URL

  Matching is described below URL 的正则表达式,匹配协议（http 或 https）、主机名、Optional port number and path.
【文本】
http://www.forta.com/blog
https://www.forta.com:80/blog/index.cfm
http://www.forta.com
http://ben:[email protected]/
http://localhost/index.php?ab=1&c=2
http://localhost:8500/
【正则表达式】

https?:\/\/[-\w.]+(:\d+)?(\/([\w\/_.]*)?)?

【结果】
http://www.forta.com/blog
https://www.forta.com:80/blog/index.cfm
http://www.forta.com
http://ben:[email protected]/
http://localhost/index.php?ab=1&c=2
http://localhost:8500/
【分析】
  https? : \ / \ / 匹配 http: / / 或 https : / /（? 使得字符 is optional）.[-\w.]+ 匹配主机名.（:\d+）? Matches an optional port number（See the example above 2 行和第 6 行）.（\ / ([ \w \ / _.]*)?)? 匹配路径：The outer subexpression matches /（如果存在的话）,The inner subexpression matches the path itself.如你所见,This mode cannot handle query strings,Also doesn't interpret the embedded correctly URL 之中的“username:password”（用户名：密码）.不过,It's more than enough to handle the vast majority URL 了（匹配主机名、端口号和路径）.
  这个匹配 URL The regular expression is not case sensitive.
  匹配 ftp 协议的 URL,把 https? 替换为 (http | https | ftp) 即可.

完整的 URL

  匹配完整的 URL 信息.
【文本】
http://www.forta.com/blog
https://www.forta.com:80/blog/index.cfm
http://www.forta.com
http://ben:[email protected]/
http://localhost/index.php?ab=1&c=2
http://localhost:8500/
【正则表达式】

https?:\/\/(\w*:\w*@)?[-\w.]+(:\d+)?(\/([\w\/_.]*(\?\S+)?)?)?

【结果】
http://www.forta.com/blog
https://www.forta.com:80/blog/index.cfm
http://www.forta.com
http://ben:[email protected]/
http://localhost/index.php?ab=1&c=2
http://localhost:8500/
【分析】
  This mode is an improvement on the previous example.this time following https?: \ / \ / 后面的是 (\w*:\w*@)?,It matches embedded in URL user name and password in （Username and password are used : 隔开,One more to follow @ 字符）,See section in this example 4 行.另外,after the path (?\S+)? Responsible for matching query strings,出现在 ? The text that follows is optional,这可以使用 ? 来表示.
  这个匹配 URL The regular expression is not case sensitive.
  Why not use this pattern instead of the previous one？就性能来说,more complex patterns,执行速度越慢.如果不需要额外的功能,It is better not to use it.

电子邮件地址

【文本】
My name is Ben Forta, and my
email address is [email protected]
【正则表达式】

(\w+\.)*\w+@(\w+\.)+[A-Za-z]+

【结果】
My name is Ben Forta, and my
email address is [email protected]
【分析】
  (\w+.)\w+ Responsible for matching the username portion of the email address（@之前的所有内容）：(\w+.) Match zero or more occurrences of text and after . ,\w+ Match required text（例如,This combination can match ben 和 ben.forta）.接下来,@匹配@字符本身.(\w+.)+ Match at least one of . 结束的字符串,[A-Za-z]+ Match the top-level domain name（com、edu、us、uk等）.
  The rules governing the validity of email address formats are extremely complex.This mode cannot verify all possible email addresses.比如说,This mode will think ben…[email protected] 是有效的（显然无效）,The hostname part is also not allowed IP 地址（This form is possible）.还是那句话,It is sufficient to verify most email addresses,So it can still be used.
  This regular expression for matching email addresses is not case sensitive.

HTML注释

   HTML Comments on the page must be in 标签之间（Both labels must contain at least two hyphens,It doesn't matter if there are more than two）.在浏览（或调试）Web页面的时候,Find out all the comments are useful.
【文本】

<!-- Start of page -->
<html>
<!-- Start of head -->
<head>
<title>My Title</title> <!-- Page title -->
</head>
<!-- Body -->
<body>

【正则表达式】

<!-{
    2,}.*?-{
    2,}>

【结果】
<!- - Start of page -->
< html>
<!- - Start of head -->
< head>
< title>My Title <!- - Page title -->
< /head>
<!- - Body -->
< body>
【分析】
   <!-{2,} 匹配 HTML The start tag of the comment,也就是 <! followed by two or more hyphens..*? 匹配 HTML The text portion of the note（Lazy quantifiers are used here）.-{2, }> 匹配 HTML The end tag of the comment.
  The pattern matches two or more hyphens,So it can also be used to find CFML 注释（the beginning of this annotation / Included in the closing tag 3 个连字符）.不过,This mode is not checked HTML Whether the number of hyphens in the comment's start tag and end tag match（可以用来检查 HTML Whether the format of the comment is incorrect）.

常用正则表达式

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