CODEWITHSUNDEEP
c#stringfile
Jason Paddle
Jason Paddle

Reputation: 1103

Extract strings from file and save in another using c#

I have .txt file with 300 000 rows. Is there any way to extract specific strings(lines) from that file and save in another .txt or excel only extracted lines ? I talk about log file where i save some requests with time taken for every request. What I want to do is to extract only the time of each request then I'll calculate average time taken.

Hope you guys understand what i talking about.

Edit: Format of .txt file is plain text and every request end with. So i have:

Starting date
//body of response from server
End date
Time: 3150,0792 ms <--- time taken

So, I have 10 000 requests and 10 000 responses. I need to extract only Time of each because will take me a lot of time manually to scroll whole .txt file and check every Time.

Upvotes: 1

Views: 2809

Answers (5)

ilmatte
ilmatte

Reputation: 1922

As others already said, it would be useful to have an example of the format. Anyway maybe you can find this tool useful:

http://filehelpers.sourceforge.net/

I use it at work and it allows you to parse and write to different file formats. Hope it helps

Upvotes: 2

oleksii
oleksii

Reputation: 35925

You can try using MemoryMappedFile and TextReader combined. MMF allows you to access large files and text reader allows you to process file in a line by line manner.

using (var mmf = 
            MemoryMappedFile.CreateFromFile(@"c:\large.data", FileMode.Open
{
    using (MemoryMappedViewStream stream = mmf.CreateViewStream())
    {
        TextReader tr = new StreamReader(stream);
        while ((line = sr.ReadLine()) != null) 
        {
            Console.WriteLine(line);
        }
    }
}

Upvotes: 4

zeFrenchy
zeFrenchy

Reputation: 6591

    private void extract_lines(string filein, string fileout)
    {
        using (StreamReader reader = new StreamReader(filein))
        {
            using (StreamWriter writer = new StreamWriter(fileout))
            {
                string line;
                while ((line = reader.ReadLine()) != null)
                {
                    if (line.Contains("what you looking for"))
                    {
                        writer.Write(line);
                    }
                }
            }
        }
    }

Upvotes: 3

Darin Dimitrov
Darin Dimitrov

Reputation: 1039160

Sure, you could use StreamReader/StreamWriter:

using (var input = File.OpenText("input.log"))
using (var output = File.CreateText("output.log"))
{
    string line;
    while ((line = input.ReadLine()) != null)
    {
        if (SomeConditionOnLine(line))
        {
            output.WriteLine(line);
        }
    }
}

This will read the input file line by line, thus having only a single line in memory at once and if this line satisfies some condition that you are looking for write it to the output file. It will be fast and consume very little memory and it will work for huge input files.

Upvotes: 3

HatSoft
HatSoft

Reputation: 11201

you can achieve it by File Class

using (StreamWriter sw = File.AppendText("File2.txt")) 
{
    foreach (string line in File.ReadLines(@"d:\File1.txt"))
    {
        if (line.Contains("TheWordInLine"))//This is the line you want by matching something
        {
                sw.WriteLine("line);
        }
    }
}

Upvotes: 4

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