How to remove extra returns and spaces in a string by regex?

Question

I convert a HTML code to plain text.But there are many extra returns and spaces.How to remove them?

Answer 1

string new_string = Regex.Replace(orig_string, @"\s", "") will remove all whitespace

string new_string = Regex.Replace(orig_string, @"\s+", " ") will just collapse multiple whitespaces into one

Answer 2

I'm assuming that you want to

• find two or more consecutive spaces and replace them with a single space, and
• find two or more consecutive newlines and replace them with a single newline.

If that's correct, then you could use

resultString = Regex.Replace(subjectString, @"( |\r?\n)\1+", "$1");

This keeps the original "type" of whitespace intact and also preserves Windows line endings correctly. If you also want to "condense" multiple tabs into one, use

resultString = Regex.Replace(subjectString, @"( |\t|\r?\n)\1+", "$1");

To condense a string of newlines and spaces (any number of each) into a single newline, use

resultString = Regex.Replace(subjectString, @"(?:(?:\r?\n)+ +){2,}", @"\n");