Shorten empty lines to one line c# Regex

Question

I have some text like

This is a line




This is other line







This is another line

How to get rid of those multi empty lines ?

What I want is

This is a line

This is other line

This is another line

\s says that matches any whitespace character (spaces, tabs, line breaks) but I cannot figure out how to make multi empty line to just one empty line ?

possible duplicate of [Replacing multiple blank lines with one blank line using RegEx search and replace](http://stackoverflow.com/questions/4475042/replacing-multiple-blank-lines-with-one-blank-line-using-regex-search-and-replac) — Tim Schmelter, Aug 31 '12 at 18:12

Sean U · Accepted Answer · 2012-08-31T18:29:06.687

Regex.Replace(input, @"(\r?\n\s*){2,}", Environment.NewLine + Environment.NewLine);

\r being optional lets it work with Unix-style line terminators. The output will have Windows-style terminators, though.

\s* allows it to match on lines that contain whitespace. (I had originally put in a ? here to make the match non-greedy, but that's not actually necessary and possibly detrimental in this case. In .NET regular expressions, \s and . don't match newlines with the default RegexOptions.)

{2,} makes sure it will only match with two successive newlines separated only by whitespace.

Shorten empty lines to one line c# Regex

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