为什么我的 C# 正则表达式在行之间不匹配？
我在 C# 中有以下正则表达式：
Regex h1Separator = new Regex(@"<h1>(?'name'[\w\d\s]+?)(<br\s?/?>)?</h1>", RegexOptions.Singleline);
尝试匹配如下所示的字符串：
<h1>test content<br>
</h1>
现在它匹配如下所示的字符串：
<h1>test content<br></h1>
<h1>test content</h1>
我做错了什么？我应该匹配换行符吗？如果是的话，C# 中的是什么？我找不到一个。
I have the following Regex in C#:
Regex h1Separator = new Regex(@"<h1>(?'name'[\w\d\s]+?)(<br\s?/?>)?</h1>", RegexOptions.Singleline);
Trying to match a string that looks like this:
<h1>test content<br>
</h1>
right now it matches strings that look like the following:
<h1>test content<br></h1>
<h1>test content</h1>
What am I doing wrong? Should I be matching for a newline character? If so, what is it in C#? I can't find one.
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（5）
您不检查 br 标签末尾和下一个标签开头之间的空格，因此它希望紧随其后看到 hr 标签。在中间添加一个 \s* 以允许这样做。
You don't check for whitespace between the end of the br tag and the start of the next tag, so it expects to see the hr tag immediately after. Add a \s* in between to allow that.
您将其定义为单行正则表达式，请参阅
RegexOptions.Singleline标志:) 使用RegexOptions.MultilineYou have it defined as a single line regex, see the
RegexOptions.Singlelineflag :) useRegexOptions.MultilineC# 中的换行符是：
\n。但是，我不熟悉正则表达式，无法告诉您如果正则表达式中有换行符会发生什么。The newline character in C# is:
\n. However, I am not skilled in regex and couldn't tell you what would happen if there was a newline in a regex expression.您可以在结束
之前在字符串中添加一个点.并保留RegexOptions.Singleline选项，或者更改它到RegexOptions.Multiline并在正则表达式中的之前添加一个$。详细信息此处you can either add a dot
.to your string before the ending</h1>and keep theRegexOptions.Singlelineoption, or change it toRegexOptions.Multilineand add a$to the regex before the</h1>. details here使用多行标志。 （编辑以解决我对 .Net 平台的误解）。
单行模式将您传入的整个字符串视为一个条目。因此
^和$表示整个字符串，而不是字符串中一行的开头和结尾。示例(?'name'[\w\d\s]+?)(
)?
将匹配以下内容：多行模式将
^和$的含义更改为字符串中每行的开头和结尾（即它们将查看每个换行符）。将匹配所需的模式：
简而言之，您需要告诉正则表达式解析器您希望使用多行。拥有一个会说您的正则表达式方言的正则表达式设计器会很有帮助。有许多。
Use the Multiline flag. (Edit to address my mispeaking about the .Net platform).
Singleline mode treats the entire string you are passing in as one entry. Therefore
^and$represent the entire string and not the beginning and ending of a line within the string. Example<h1>(?'name'[\w\d\s]+?)(<br\s?/?>)?</h1>will match this:Multiline mode changes the meaning of
^and$to the beginning and ending of each line within the string (i.e. they will look at every line break).will match the desired pattern:
In short, you need to tell the regex parser you expect to work with multiple lines. It helps to have a regex designer that speaks your dialect of regex. There are many.