Question

I am replacing all occurances of with the <BR> tag, but for some reason the text entered has many in a row, so I need to combine them.

Basically, if more than 1 occur together, replace it with just a single <BR> tag.

Can someone help me with this?

Answer 1

This will replace any sequence of carriage-returns () and/or linefeeds () with a single <br />:

string formatted = Regex.Replace(original, @"[
]+", "<br />");

If you only want to replace sequences of two or more items then the simplistic answer is to use the {2,} quantifier (which means "at least two repetitions") instead of + (which means "at least one repetition"):

string formatted = Regex.Replace(original, @"[
]{2,}", "<br />");

Note that the expression above will treat the common CR+LF combination as a sequence of two items. It s probable that you ll want to treat CR+LF as a single item instead, in which case the expression becomes slightly more complicated:

string formatted = Regex.Replace(original, @"(?:
|
(?!
)|(?<!
)
){2,}", "<br />");

Answer 2

Use the following code:

str = Regex.Replace(str, @"[
]+", "<br />");

It could well be faster to call the normal Replace method multiple times and not use a Regex at all, like this:

int oldLength;
do {
    oldLength = str.Length;
    str = str.Replace( 
 ,  
 );
    str = str.Replace("

", "
");
} while(str.Length != oldLength);

str = str.Replace("
", "<br />");

Answer 3

Note that string.Replace() is much faster than using RegEx:

string result = oldString.Replace("

","
");
result = result .Replace("
","<br>");

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