CODEWITHSUNDEEP
c#regexpattern-matchingmatching
Gigg
Gigg

Reputation: 1049

Regex and remove not working properly

I have some doubts about what I'm doing. I try to remove pices of text like the letter "n" where it is between a "(" and a " " or viceversa, and many other cases. I use regex to find the pattern, but how can I delete only the letter?

I've used this: "[( ]" + mystring + @"[)= \-\*]"

like this:

foreach(Match mm in Regex.Matches(SourceCode, @"[( ]" + mystring + @"[)= \-\*]"))
{   
    int lng= mm.Length;
    SourceCode = SourceCode.Remove(mm.Index + 1, lng- 2);
}

The problem is that it calculates the index for the original text, and if there will be removed a "n" the index for the next match will be decalated with one and will delete from a wrong place. Really strange.

Does anybody know what it is doing that?

Or maybe do you have a better ideea?

Edit:

I can't use replace. Let's say I want to delete "n" where n is like "(n " so if I use replace it will delete all those three characters wich I don want. If I use replace only for n, it will delete wrong letter like the "n" from "and" . . .

Upvotes: 0

Views: 98

Answers (1)

Tim Pietzcker
Tim Pietzcker

Reputation: 336128

Your question is a bit hard to read, but I think what you need is a replace operation, together with lookaround assertions:

SourceCode = Regex.Replace(SourceCode, "(?<=[( ])" + mystring + "(?=[)= *-])", "");

This will replace the regex mystring with nothing, but only if it is preceded by a ( or space, and followed by ), =, *, - or space.

If you want mystring to be interpreted as a string, not as a regex, you should use Regex.Escape(mystring) instead of mystring.

Upvotes: 4

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