vb.net 修改 CSV 文件中的列

Question

我有一个包含许多行的 CSV 文件，我需要在其中使用 VB.NET 更新/替换第四列的值。列上没有标题，因此循环可以从第一行开始。

infile.csv
"value1","value2","value3","value4"

经过大量谷歌搜索，有很多关于如何读取和写入 CSV 文件的示例，但没有一个是真正需要的。我知道有多种方法可以完成这项任务，但要求是使用 VB.NET 完成。任何帮助将不胜感激。

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从 Marco 的 C# 答案移植的最终代码

    Private Sub CSVmod(ByVal strFileName As String, ByVal newFileName As String)

    Dim strLines As String() = File.ReadAllLines(strFileName)
    Dim strList As New List(Of String)
    Dim strReplace As String = "test"

    For Each line In strLines
        Dim strValues As String() = line.Split(",")
        If (strValues.Length = 14) Then
            strValues(3) = strReplace

            strList.Add(String.Join(",", strValues))
        End If

    Next

    File.WriteAllLines(newFileName, strList.ToArray())

Answer 1

对不起，我只能用 C# 编写它。
我认为转换到 VB.NET 不会有很多问题。
这是我的代码：

private void SubstFile(string filename, string newFileName)
{
    // Reading all rows of the file
    string[] lines = File.ReadAllLines(filename);

    List<string> list = new List<string>();
    foreach (string line in lines)
    {
        // For every row I split it with commas
        string[] values = line.Split(',');
        // Check to have 4 values
        if (values.Length == 4)
        {
            // Substitute fourth value
            values[3] = "new value";
            // Add modified row to list
            list.Add(String.Join(",", values));
        }
    }
    // Save list to new file
    File.WriteAllLines(newFileName, list.ToArray());
}

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VB.NET 版本：

Private Sub SubstFile(filename As String, newFileName As String)
    ' Reading all rows of the file
    Dim lines As String() = File.ReadAllLines(filename)

    Dim list As List(Of String) = New List(Of String)()
    For Each line As String In lines
        ' For every row I split it with commas
        Dim values As String() = line.Split(","c)
        ' Check to have 4 values
        If values.Length = 4 Then        
            ' Substitute fourth value
            values(3) = "new value"
            ' Add modified row to list
            list.Add(String.Join(",", values))
        End If
    Next
    ' Save list to new file
    File.WriteAllLines(newFileName, list.ToArray())
End Sub

Answer 2

使用python....一行代码

df = pandas.read_csv('file.csv)