从文本文件中删除最后一行 [英] Strip the last line from a text file

问题描述

我需要从文本文件中删除最后一行.我知道如何在C#中打开和保存文本文件，但是如何去除文本文件的最后一行?

I need to strip the last line from a text file. I know how to open and save text files in C#, but how would I strip the last line of the text file?

文本文件的大小总是不同的(有些行有80行，有些行有20行).

The text file will always be different sizes (some have 80 lines, some have 20).

有人可以告诉我该怎么做吗?

Can someone please show me how to do this?

谢谢.

推荐答案

使用少量的行，您可以轻松地使用类似的东西

With a small number of lines, you could easily use something like this

string filename = @"C:\Temp\junk.txt";

string[] lines = File.ReadAllLines(filename);
File.WriteAllLines(filename, lines.Take(lines.Count() - 1));

但是，随着文件变大，您可能希望使用类似

However, as the files get larger, you may want to stream the data in and out with something like this

string filename = @"C:\Temp\junk.txt";
string tempfile = @"C:\Temp\junk_temp.txt";

using (StreamReader reader = new StreamReader(filename))
{                
    using (StreamWriter writer = new StreamWriter(tempfile))
    {
        string line = reader.ReadLine();

        while (!reader.EndOfStream)
        {
            writer.WriteLine(line);
            line = reader.ReadLine();
        } // by reading ahead, will not write last line to file
    }
}

File.Delete(filename);
File.Move(tempfile, filename);

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