CODEWITHSUNDEEP
c#regex
Alan Wayne
Alan Wayne

Reputation: 5384

How to replace multiple \r\n in a RichTextBox document with Regex?

I've tried dismally. I have paragraphs consisting of Runs in a RichTextBox. Each run consists of a string with none, one, or many embeded "\r\n". I need to remove all but the first "\r\n" when there are more then one together and replace the remaining "\r\n" with "| ". The Document will have many such paragraphs.

That is, given this string:

This \r\n is a \r\n\r\n Test. Or, \r\n\r\n\r\n this \r\n.

I need this string:

This | is a | Test. Or, | this | .

How can this be done using Regex (C# .Net 4.5)?

TIA (I've studied similar questions, but can't seem to get it right :()

Edit: Thanks to all who helped. For anyone coming here, in my case the correct answer is actually a combination of the answers I received. That is, both of these work correctly in my case.

    Regex.Replace(s, "(\r\n)+", "| ")   
    Regex.Replace(s, @"(\r\n)+","| ")

Upvotes: 0

Views: 98

Answers (2)

Valdi_Bo
Valdi_Bo

Reputation: 30981

I assume, you have pairs of CF/LF chars, not \ + r + \ + n.

If this is the case, you should not use here verbatim strings (with @ before the actual string).

Writing @"xx\r\n" causes that such a string contains:

  • 2 x chars,
  • a backslash and r,
  • a backslash and n.

The same for regex.

If you don't believe, run the following code:

string s = @"This \r\n is a \r\n\r\n Test. Or, \r\n\r\n\r\n this \r\n.";
Console.WriteLine(s);

You should write:

string s = "This \r\n is a \r\n\r\n Test. Or, \r\n\r\n\r\n this \r\n.";
string n = Regex.Replace(s, "(\r\n)+", "|");
Console.WriteLine(n);

Upvotes: 1

Mong Zhu
Mong Zhu

Reputation: 23732

Here is a working example:

string s = @"This \r\n is a \r\n\r\n Test. Or, \r\n\r\n\r\n this \r\n.";

string n = Regex.Replace(s, @"(\\r\\n)+", "|");

Console.WriteLine(n);

Output:

This | is a | Test. Or, | this |.

the + sign at the end of the pattern means 1 or more occurrences of the previous characters. This way it will also capture multiple \r\n\r\n

Upvotes: 2

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