Question

我正在尝试编辑我的csv中的一个列。但是代码似乎不会影响文件。我尝试进行的更改是更改为使用逗号分隔第4列数据。

class Program
{
    static void Main(string[] args)
    {
        var filePath = Path.Combine(Directory.GetCurrentDirectory(), "kaviaReport 02_08_2016.csv");
        var fileContents = ReadFile(filePath);
        foreach (var line in fileContents)
        {
            Console.WriteLine(line);
        }

        Console.WriteLine("Press any key to exit...");
        Console.ReadKey();
    }

    public static IList<string> ReadFile(string fileName)
    {
        var results = new List<string>();
        int lineCounter = 0;
        string currentLine = string.Empty;
        var target = File
 .ReadAllLines(fileName);
        while ((currentLine = fileName) != null)//while there are lines to read
        {
            List<string> fielded = new List<string>(currentLine.Split(','));
            if (lineCounter != 0)
            {
                //If it's not the first line
                var lineElements = currentLine.Split(',');//split your fields into an array
                var replace = target[4].Replace(' ', ',');//replace the space in position 4(field 5) of your array
                results.Add(replace);
                //target.WriteAllLines(string.Join(",", fielded));//write the line in the new file

            }

            lineCounter++;
            File.WriteAllLines(fileName, target);


        }

        return results;
    }
}

Answer 1

当前代码有一些错误最大的一个是currentLine到fileName的分配。如果你想循环遍历这一点，这当然没有意义。因此，您需要在读取线上使用foreach 然后在循环内部，您应该使用变量lineElements在分割currentLine后获得5列。最后，文件的重写超出了循环范围，应该使用结果列表。

// Loop, but skip the first line....
foreach(string currentLine in target.Skip(1))
{
    // split your line into an array of strings
    var lineElements = currentLine.Split(',');

    // Replace spaces with commas on the fifth column of lineElements 
    var replace = lineElements[4].Replace(' ', ',');

    // Add the changed line to the result list 
    results.Add(replace);
}

// move  outside the foreach loop the write of your changes 
File.WriteAllLines(fileName, results.ToArray());

在编写此代码时，我脑海中浮现出一些东西。目前尚不清楚是否要重写CSV文件只包含用逗号扩展的第五列中的数据，或者是否要重写整行（也是第0,1,2,3,4列等等）后一种情况你需要一个不同的代码

// Replace spaces with commas on the fifth column of lineElements 
// And resssign the result to the same fifth column
lineElements[4] = lineElements[4].Replace(' ', ',');

// Add the changed line to the result list putting the comma 
// between the array of strings lineElements
results.Add(string.Join(",", lineElements);

Answer 2

while ((currentLine = fileName) != null)将设置currentLine = fileName，这将使该行始终为true并进行无限循环

我会把它写成for循环而不是一会儿

public static IList<string> ReadFile(string fileName)
    {
        var target = File.ReadAllLines(fileName).ToList();
        // i = 1 (skip first line)
        for (int i = 1; i < target.Count; i++)
        {
           target[4] = target[4].Replace(' ', ','); //replace the space in position 4(field 5)
        }
        File.WriteAllLines(fileName, target);
        // Uncomment the RemoveAt(0) to remove first line
        // target.RemoveAt(0);
        return target;
    }

编辑Csv文件中的一列

2 个答案: