Regex for removing a specific BBCode from a string

问题:

I'm trying to write a simple method for removing specific BBCodes from an input string.

For example, where I have an input of:

string input = "[b]Hello World![/b]";

I would want to be able to do:

Remove(input, "b");

And get an output of:

"Hello World!"

Regex really isn't my strong suit. I've managed to piece together the following from google:

public static string Remove(string input, string code)
{
    string pattern = string.Format(@"\[{0}\].*?\[\/{1}\]", code, code);

    return Regex.Replace(input, pattern, string.Empty, RegexOptions.IgnoreCase);
}

Unfortunately this returns an empty string for my given example.

Can anyone advise me on how I can correct my regex to get the desired output?

Thanks

回答1:

Use this simple regex: \[/?{0}\]

Your regex is removing the whole string

• Your regex \[{0}\].*?\[\/{1}\] is removing the entire [b]...[/b] string. That's why you are getting an empty string from the replacement.

• What you need is to remove only the [b] and [b]. In normal regex, this is expressed quite simply with \[/?b\], where the slash is made optional by the ?

• In your parametrized regex, something like \[/?{0}\] will work.

回答2:

The below regex would capture the string Hello World! inside the second group.

^(.*?)((?<=])[^[]*)(.*)$

DEMO

So replace all your input string with the second captured group.

回答3:

If you sure that both starting and trailing special symbol must occur and you don't want them to be in a result, you can use positive look back ((?<=(your symbols here))) and positive look ahead ((?=(your symbols here))) for specified characters.

Complete answer will look like this:

(?<=(\[{0}\])).*(?=(\[\/{1}\]))