Remove line from a file

Question

I tried to remove a line from text file which contains a particular word. However I need a better approach to delete the line.

Here is the code I used:

 var oldLines = System.IO.File.ReadAllLines(filepath);
            var newLines = oldLines.Where(line1 => !line1.Contains("Value"));
            System.IO.File.WriteAllLines(filepath, newLines);

By using this my task was completed, but with the following performance issues: If the file contains 10 lakhs lines it must read 10lakhs line and write 10 lakhs lines, so it takes more time.

Had to Google a "lakh". for anyone outside of Asia who's also never heard of this term: it's 100.000. — Thomas Mulder, Jun 01 '16 at 09:07

Sajeetharan · Answer 1 · 2014-03-19T12:29:39.857

1

string line = null;
string line_to_delete = "sample line i want to delete";

using (StreamReader reader = new StreamReader("C:\\input")) {
    using (StreamWriter writer = new StreamWriter("C:\\output")) {
        while ((line = reader.ReadLine()) != null) {
            if (String.Compare(line, line_to_delete) == 0)
                continue;   
            writer.WriteLine(line);
        }
    }
}

edited Mar 19 '14 at 12:29

answered Mar 19 '14 at 12:19

Sajeetharan

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you might have forgotten to actually write anything – decPL Mar 19 '14 at 12:20
not quite - OP said delete whole line if it contains given string. Also OP's post expects same file to be overwritten. – Chris Ballard Mar 19 '14 at 12:22

Remove line from a file

1 Answers1