读取和操作 .csv 文件答案

【问题标题】：Reading from and manipulating a .csv file读取和操作 .csv 文件
【发布时间】：2013-05-08 00:25:40
【问题描述】：

我每个月都有多个 .csv 文件，如下所示：

01/04/2012,00:00,7.521527,80.90972,4.541667,5.774305,7,281.368
02/04/2012,00:00,8.809029,84.59028,6.451389,5.797918,7,274.0764
03/04/2012,00:00,4.882638,77.86806,1.152778,15.13611,33,127.6389
04/04/2012,00:00,5.600694,50.35417,-3.826389,15.27222,33,40.05556

格式为：日期格式为dd/mm/yy、当前时间、当前温度、当前湿度、当前露点、当前风速、当前阵风、当前风向

程序需要计算平均值温度湿度风速风向

并将它们显示在文本框中。

有什么想法吗？

这是我到目前为止所做的......

Option Strict On
Option Explicit On

Imports System.IO
Imports System

Public Class Form1   

Private Sub cmb1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmb1.SelectedIndexChanged

End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnexit.Click
    Me.Close()
End Sub

Private Sub btn1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btndata.Click
    'This is for August
    If cmb1.SelectedIndex = 1 Then
        TextBox1.Clear()
        Using reader As New StreamReader("c://temp/DailyAug12log.csv")
            Dim line As String = reader.ReadLine()
            Dim avgTemp As Integer
            Dim fields() As String = line.Split(",".ToCharArray())
            Dim fileDate = CDate(fields(0))
            Dim fileTime = fields(1)
            Dim fileTemp = fields(2)
            Dim fileHum = fields(3)
            Dim fileWindSpeed = fields(4)
            Dim fileWindGust = fields(5)
            Dim fileWindBearing = fields(6)

            While line IsNot Nothing
                counter = counter + 1
                line = reader.ReadLine()
            End While
            avgTemp = CInt(fields(2))
            avgTemp = CInt(CDbl(avgTemp / counter))
            TextBox1.Text = TextBox1.Text & "Month = August" & vbCrLf & "Temperature Average: " & avgTemp & vbCrLf
        End Using
    End If
End Sub

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    Dim files() As String
    files = Directory.GetFiles("C:\Temp", "*.csv", SearchOption.AllDirectories)
    For Each FileName As String In files
        cmb1.Items.Add(FileName.Substring(FileName.LastIndexOf("\") + 1, FileName.Length - FileName.LastIndexOf("\") - 1))
    Next
End Sub
End Class

【问题讨论】：

您需要另一个变量来跟踪您已阅读的行数。只需为每一行增加一个。然后将您的“总”变量除以行数，并使用计算值更新您的文本框。您也可以声明其他“总计”变量来总计其他测量值...
感谢我正在努力！关于如何添加它的任何想法？谢谢！
严重吗？...在与“total”变量相同的位置/时尚中声明行的计数器。它将是整数类型。在您累积总变量的同一位置将该变量加一。你认为你应该计算while循环内部还是外部的平均值？平均值应该使用什么数据类型？整数还是双精度数？
您好，我试过了，但我的计数器不工作。它将我的平均值计算为 0。我在 while 循环内有计数器，在循环外计算平均值。你能给我一个你认为我应该做什么的例子吗？
我已经用我现在拥有的代码更新了上面的代码，谢谢

标签： vb.net

【解决方案1】：

Private Class Weather
    Public SampleTimeStamp AS Date
    Public Temperature AS Double
    Public Humidity As Double
    Public WindSpeed AS Double
    Public WindBearing AS Double
End Class

Sub Main
    Dim samples = ReadFile("c://temp/DailyAug12log.csv")

    Dim avgTemperature = samples.Average(Function(s) s.Temperature)
    ...
End Sub

Private Function ReadFile(ByVal fileName as String) AS List(Of Weather)
    Dim samples As New List(Of Weather)
    Using tfp As new TextFieldParser(filename)
        tfp.Delimiters = new String() { "," }
        tfp.TextFieldType = FieldType.Delimited

        While Not tfp.EndOfData
            Dim fields = tfp.ReadFields()
            Dim sample As New Weather()

            sample.SampleTimeStamp = Date.ParseExact(fields(0) & fields(1), "dd\/MM\/yyyyHH\:mm", CultureInfo.InvariantCulture)
            sample.Temperature = Double.Parse(fields(2), CultureInfo.InvariantCulture)
            sample.Humidity = Double.Parse(fields(3), CultureInfo.InvariantCulture)
            sample.WindSpeed = Double.Parse(fields(4), CultureInfo.InvariantCulture)
            sample.WindBearing = Double.Parse(fields(5), CultureInfo.InvariantCulture)
            samples.Add(sample)
        End While

        Return samples
    End Using
End Function

【讨论】：

谢谢！我如何将每个的平均值显示到文本框中？ :)
TextBox.Text = String.Format(CultureInfo.CurrentCulture, "平均温度为 {0}", avgTemperature)

【解决方案2】：

我不会使用这种方法 - 如果列的顺序发生变化，您的程序将显示错误的结果。我会使用像 http://kbcsv.codeplex.com/ 这样的好的 csv 阅读器，并将数据读取到数据表中。那么你可以很容易和可靠地计算你的结果列，因为你可以像 MyDatatable.Cooumns["Headername"] 一样对每一列进行寻址。

【讨论】：