Saeid Yazdani Saeid Yazdani - 3 months ago 29
C# Question

How to remove empty lines from a formatted string?

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

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

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

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