Question

我编写了一个将txt文件拆分成小块的程序但我的问题是我的方法很慢因为这个文件大小是1gb，我使用一个名为“pagesize”的变量，它将根据分割文件中的行数计算

问题是foreach很慢？

有更好的方法吗？

 private void button1_Click(object sender, EventArgs e)
    {
        string inputFile = @"G:\Programming\C#\c# tamrin reza\large-Orders.txt";

        int seed = 1000;
        const int pageSize = 5000;
        int count = 1;
        const string destinationFileName = @"F:\Output\";
        string outputFile;
        string baseName = "-CustomerApp";
        string extension = Path.GetExtension(inputFile);
        var lst = new List<string>();
        //FileInfo fileInfo = new FileInfo(inputFile);
        //long fileSize = fileInfo.Length / pageSize;
        FileStream fs = new FileStream(inputFile, FileMode.Open);
        StreamReader sr = new StreamReader(fs);
        while (!sr.EndOfStream)
        {
            for (int j = 1; j <= pageSize; j++)
            {
                var line = sr.ReadLine();
                lst.Add(line);
            }
            outputFile = destinationFileName + count + baseName + extension;
            CopyLines(lst, outputFile);
            lst.Clear();
            count++;
        }
    }

    private void CopyLines(List<string> line, string outputFile)
    {
        FileStream outputFileStream = new FileStream(outputFile, FileMode.Create, FileAccess.Write);
        //StreamWriter writer = new StreamWriter(outputFile);
        //for (int i = 1; i < line.Count; i++)
        //{
        //}
        using (StreamWriter sw = new StreamWriter(outputFileStream))
        {
            foreach (var li in line)
            {
                sw.WriteLine(li);
            }
        }
    }

由于

Answer 1

您正在迭代整个集合两次。如果您在阅读时写入输出文件，那么将在整个集合中保存一次迭代。

    while (!sr.EndOfStream)
    {
        outputFile = destinationFileName + count + baseName + extension;
        FileStream outputFileStream = new FileStream(outputFile, FileMode.Create, FileAccess.Write);

        using (StreamWriter sw = new StreamWriter(outputFileStream))
        {
            for (int j = 1; j <= pageSize; j++)
            {
                var line = sr.ReadLine();
                sw.WriteLine(li);
            }
        }
        lst.Clear();
        count++;
    }

难度慢速分割器文件txt？

1 个答案: