How to read a text file from last line to first line in c#

Question

Possible Duplicate:
How to read a text file reversely with iterator in C#

I wanted to know how to read a text file from last line to first line in c#.

I am using this code for reading a text file

            using (var sr = File.OpenText("C:\\test.txt"))
            {
                string line;
                bool flag = true;
                while ((line = sr.ReadLine()) != null)
                {
                }
            }

I dont know how to read Backwards.

There would be a great appreciation if someone could help me.

Thanks In Advance.

Do check http://stackoverflow.com/questions/452902/how-to-read-a-text-file-reversely-with-iterator-in-c-sharp, it specifically mentions not reading the entire file into memory which the answers posted here so far seem to be doing. — Miserable Variable, Oct 27 '11 at 12:01

score 10 · Answer 1 · answered Oct 27 '11 at 11:52

10

File.ReadAllLines(@"C:\test.txt").Reverse()

answered Oct 27 '11 at 11:52

Joe White

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Great, mine is nonsense and will be deleted. – Fischermaen Oct 27 '11 at 11:55
@SharrokG Fine, so be nice, accept his answer and give him the points. ;-) – Fischermaen Oct 27 '11 at 12:03
how can i use this in my code to read reverse can u pls say me – Sharrok G Oct 27 '11 at 12:05
@SharrokG, I take it you've never used C# before? Try this: `var reversedLines = File.ReadAllLines(@"C:\test.txt").Reverse(); foreach (var line in reversedLines) DoSomething(line);` where you write the `DoSomething` part. – Joe White Oct 27 '11 at 13:02
2

Too bad answer for performance wise.. – yakya Mar 03 '19 at 10:47

score 2 · Accepted Answer · answered Oct 27 '11 at 11:51

2

Try to reverse the collection of read lines

    List<string> lines = new List<string>();
    using (var sr = File.OpenText("C:\\test.txt"))
    {
        string line;
        while ((line = sr.ReadLine()) != null)
        {
            lines.Add(line); 
        }
    }

    lines.Reverse();

answered Oct 27 '11 at 11:51

Stecya

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Joe Whites solution is much better, because it uses only one file access. – Fischermaen Oct 27 '11 at 12:28
I suggest to try with a file sized a couple of Gigabytes... – Felice Pollano Jul 17 '19 at 09:55

How to read a text file from last line to first line in c#

2 Answers2