将PHP正则表达式转换为c＃

问题描述：

I have this regex:

<DIV(?:(?!</DIV>).)*?"(http://www\.foo\.com(?:\\.|[^"\\])*)"

And I am trying to use it using c#:

 @"<DIV(?:(?!</DIV>).)*?""(http://www\.foo\.com(?:\\.|[^""\\])*)"""

But this outputs every thing from <DIV onward I want it to just show inside the ""

Like the actual regex does

我有这个正则表达式： p>

 ＆lt; DIV（？  ：（？！＆LT; / DIV＆GT;））* “（HTTP：// WWW \包含.foo \ .COM（：\\ | [^？” \\]）*）“
 代码>。？   pre> 
 
 我正在尝试使用c＃： p> 
 
 
  @“＆lt; DIV（？:(？！＆lt; / DIV＆gt  ？;））* “”？（HTTP：// WWW \包含.foo \ .COM（：\\ | [^ “” \\]）*） “”“
 代码>  PRE>  
 
 但是从＆lt; DIV  code>开始输出
every东西我希望它只显示在“” code>  p> 
 
  
 与实际正则表达式一样 strong>  p> 
  div>

答

Since you are using capture groups (groups between a pair of parentheses ()), you will have to use Groups[#] to get the different parts of the capture group. Groups[1] will have the value of the first capture group.

If you are using:

@"<DIV(?:(?!</DIV>).)*?""(http://www\.foo\.com(?:\\.|[^""\\])*)"""

You will get the ones between " by using Groups[1].Value and the whole match in Groups[0].Value.

Example:

@"a(b(cd)(ef))"

Here you have 3 capture groups because there are 3 pairs of parentheses. After a match, and if you use:

Console.WriteLine(match.Groups[0].Value);
Console.WriteLine(match.Groups[1].Value);
Console.WriteLine(match.Groups[2].Value);
Console.WriteLine(match.Groups[3].Value);

You get:

abcdef
bcdef
cd
ef

If that's a little confusing, maybe this breakdown can help:

a(b(cd)(ef))
 1 2   3
   ^--|^--|
 ^---------|

The numbers and ^ indicate the beginning of the capture groups.

答

string str = "<DIV src=\"http://www.foo.com\"></DIV>";
Regex re = new Regex(@"<DIV(?:(?!<\/DIV>).)*?\""(http:\/\/www\.foo\.com(?:\\.|[^\""\\])*)\""");
// or Regex re = new Regex(@"<DIV(?:(?!</DIV>).)*?""(http://www\.foo\.com(?:\\.|[^""\\])*)""");

Match match = re.Match(str);
Console.Write(match.Groups[1]); // Returns "http://www.foo.com"

将PHP正则表达式转换为c＃

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