如何使用streamreader读取csv时跳过第一行

Question

我有以下代码来从 CSV 文件读取值并进行一些处理。我想跳过输入 CSV 文件的第一行，因为它包含标题文本，但我想在处理完成后将其添加回来。

List<string> values = new List<string>();
using (StreamReader sr = new StreamReader(filePath))
{
    while (sr.Peek() != -1)
    {
        string line = sr.ReadLine();
        List<string> lineValues = line.Split(',').ToList();
        var tempMinInt = 1;
        var tempValue = 1;
        var tempValInt = Convert.ToInt32(lineValues[4]);
        if (lineValues[3] == "1876")
        {
            if (tempValInt % 60 != 0)
            {
                tempMinInt = (tempValInt / 60) + 1;
                tempValue = tempMinInt * 30;
            }
            else
            {
                tempMinInt = tempValInt / 60;
                tempValue = tempMinInt * 30;
            }
        }
        else if (lineValues[3] == "1875")
        {
            if (tempValInt != 0)
            {
                tempValue = 500;
            }
            else
                tempValue = 0;
        }

        if (lineValues[3] == "1876")
        {
            values.Add(string.Join(",", lineValues) + "," + "0" + "," + "30" + "," + tempValue.ToString());
        }
        else if (lineValues[3] == "1875")
        {
            values.Add(string.Join(",", lineValues) + "," + "1" + "," + "500" + "," + tempValue.ToString());
        }

    }
}

示例输入 csv 如下所示：

id, datetime, msisdn, num, duration
33083,2011-12-19 05:17:57+06:30,98590149,1875,258
33084,2011-12-19 05:22:28+06:30,98590149,1875,69
33085,2011-12-19 05:23:45+06:30,98590149,1875,151
33086,2011-12-19 05:30:21+06:30,98590149,1875,58
33087,2011-12-19 06:44:19+06:30,949826259,1875,66

我希望输出如下所示：

id, datetime, msisdn, num, duration, type, ammount, total
33083,2011-12-19 05:17:57+06:30,98590149,1875,258,1,500,500
33084,2011-12-19 05:22:28+06:30,98590149,1875,69,1,500,500
33085,2011-12-19 05:23:45+06:30,98590149,1875,151,1,500,500
33086,2011-12-19 05:30:21+06:30,98590149,1875,58,1,500,500

Answer 1

您可以在 while 循环之前读取第一行并将其存储，或者您可以使用计数器/布尔字段来检查您在文件中的位置。

Answer 2

When lineNumber is 1, it will skip the execution part and not process anything from first row.   


string doWork = string.Empty;

   var lineNumber = 1;

   using (StreamReader reader = new StreamReader(fileLocation))
            {
                while (!reader.EndOfStream)
                {
                    var line = reader.ReadLine();

                    var docLine = line.Split(',');

                    if (!String.IsNullOrEmpty(line.ToString()))
                    {
                        if (lineNumber != 0)
                        {
                            if (lineNumber > 1)
                            {
                                doWork = "Excecuting";
                            }
                        }
                        lineNumber++;
                    }
                }
            }

Answer 3

在进入循环之前先阅读它。我会这样做：（

using (StreamReader sr = new StreamReader(filePath))
{
    string headerLine = sr.ReadLine();
    string line;
    while ((line = sr.ReadLine()) != null)
    {
         ...
    }
}

我个人不喜欢使用 Peek。）

然后，当您写出输出时，从 headerLine 开始。

从 C# 7 开始，模式匹配让这变得更加愉快：

using (StreamReader sr = new StreamReader(filePath))
{
    string headerLine = sr.ReadLine();
    while (sr.ReadLine() is string line)
    {
          ...
    }
}

Answer 4

只需阅读第一行，然后不执行任何操作...

List<string> values = new List<string>();
using (StreamReader sr = new StreamReader(filePath))
{
    sr.ReadLine();
    while (sr.Peek() != -1)
    {
        string line = sr.ReadLine();
        List<string> lineValues = line.Split(',').ToList();

        //***//
    }
}

Answer 5

像这样的事情：

bool isFirst=true;
using (StreamReader sr = new StreamReader(filePath))
{
    while (sr.Peek() != -1)
    {
        if(isFirst)
        {
            isFirst=false;
            continue;
        }
    }
}

Answer 6

我建议，使用技术来处理这种情况，

                int row = 0;
                using (StreamReader sr = new StreamReader(filePath))

                {
                   While(reader.Read()) //Each row of the file
                    {
                        row++;
                        if(row==1)
                        {
                            continue;
                        }
               }
... code..
}