How to remove empty lines from a formatted string?

c# regex string stringbuilder
Saeid Yazdani picture Saeid Yazdani · Oct 4, 2011 · Viewed 69k times · Source

How to remove empty lines in a string in C#? I am generating some text files in C# (winforms) and for some reason there are some empty lines. How can I remove them after the string is generated (using StringBuilder and TextWrite).

Example text file: 

THIS IS A LINE



THIS IS ANOTHER LINE AFTER SOME EMPTY LINES!

Thanks.

Answer

Tim Pietzcker picture Tim Pietzcker · Oct 4, 2011

If you also want to remove lines that only contain whitespace, use

resultString = Regex.Replace(subjectString, @"^\s+$[\r\n]*", string.Empty, RegexOptions.Multiline);

^\s+$ will remove everything from the first blank line to the last (in a contiguous block of empty lines), including lines that only contain tabs or spaces.

[\r\n]* will then remove the last CRLF (or just LF which is important because the .NET regex engine matches the $ between a \r and a \n, funnily enough).

Related questions

Find and extract a number from a string

I have a requirement to find and extract a number contained within a string. For example, from these strings: string test = "1 test" string test1 = " 1 test" string test2 = "test 99" How can I do this?

Read More
How do I replace multiple spaces with a single space in C#?

How can I replace multiple spaces in a string with only one space in C#? Example: 1 2 3 4 5 would be: 1 2 3 4 5

Read More
Get string between two strings in a string

I have a string like: "super exemple of string key : text I want to keep - end of my string" I want to just keep the string which is between "key : " and " - ". How can I do that? Must I …

Read More