为什么\b不使用正则表达式.NET词相匹配 [英] Why \b does not match word using .net regex

问题描述

要定期复查我expresions阅读本教程 。不管怎么说该教程提到 \b 字边界（\w和\W字符之间）匹配。该教程还给出了一个链接，您可以安装快报（程序创建正则表达式时，可以帮助）。

To review regular expresions I read this tutorial. Anyways that tutorial mentions that \b matches a word boundary (between \w and \W characters). That tutorial also gives a link where you can install expresso (program that helps when creating regular expressions).

所以，我创建了我在快报的正则表达式，我也inded得到匹配。现在，当我同样的正则表达式复制到Visual Studio我没有得到匹配。请看下图：

So I have created my regular expressions in expresso and I do inded get a match. Now when I copy the same regex to visual studio I do not get a match. Take a look:

为什么我没有得到匹配？在即时窗口中我显示可变输出的内容。在快报我得到了根火柴，在Visual Studio中我不知道。为什么？

Why am I not getting a match? in the immediate window I am showing the content of variable output. In expresso I do get a match and in visual studio I don't. why?

推荐答案

C＃编译器被拦截在您的字符串的\b并将其转换为ASCII退格字符。你需要让你的字符串逐字（前缀与在符号）左右反斜杠传递给正则表达式，像这样的双逃脱'B'：

The C# compiler is intercepting the \b in your string and converting it into an ASCII backspace character. You need to make your string verbatim (prefix with an at-symbol) or double-escape the 'b' so the backslash is passed to RegEx like so:

@"\bCOMPILATION UNIT";

或

"\\bCOMPILATION UNIT"

我会说的.NET正则表达式文档没有明确这一点。我花了，而在第一次过这个号码

I'll say the .NET RegEx documentation does not make this clear. It took me a while to figure this out at first too.

趣味-的事实：在 \r 和 \\\
（分别是回车和换行）字符和其他一些人被两个正则表达式和C＃语言识别，所以最终的结果是一样的，甚至如果编译串是不同的。

Fun-fact: The \r and \n characters (carriage-return and line-break respectively) and some others are recognized by both RegEx and the C# language, so the end-result is the same, even if the compiled string is different.

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