使用C＃正则表达式如何将竖线作为文字匹配？

Question

I'm writing a program in C# using Microsoft Visual Studio, i need the program to match the vertical bar, but when I try to escape it like this "\\|" it gives me an unrecognized escape sequence error. What am I doing wrong?

Answer 1

In C#

string test = "\|";

Is going to fail because this is a C# string escape sequence, and no such escape exists. Because you are trying to include a backslash in the string, you need to escape the slash so the string actually contains a slash:

string test = "\\|";

What will actually be stored in this string is \\|

Answer 2

The reason you get an unrecognized escape sequence is that backslash is used as an escape character in C# string literals as well as in regex.

You have several choices to fix this:

• Use verbatim literals, ie @"\\|" , or
• Use a second escape inside a regular literal, ie "\\\\|" , or
• Use a character class, ie [|]

The third one is my personal favorite, because it does not require counting backslashes.

Answer 3

The string is treating "\\|" as an escaped pipe in C#. Try "\\|" to escape the \\ so that the regex actually sees the \\| you want.