带子字符串的VB.net拆分函数_Vb.net

带子字符串的VB.net拆分函数

vb.net

带子字符串的VB.net拆分函数,vb.net,Vb.net,我想读取字符串中的某个值。每行都是一个新字符串，我想读取每行的第6个整数 Public Class Form1 Private Sub Button1_Click(sender As Object, e As EventArgs) Handles browsebtn.Click If OpenFileDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then Dim filename As String = OpenFi

我想读取字符串中的某个值。每行都是一个新字符串，我想读取每行的第6个整数

Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles browsebtn.Click
    If OpenFileDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then
        Dim filename As String = OpenFileDialog1.FileName
        Dim streamreader As New System.IO.StreamReader(filename)
        Dim textfile As String = streamreader.ReadToEnd
        Dim splitChar As String = vbNewLine
        Dim day As Integer = textfile.Substring(10, 2)
        Dim strLine() As String = day.Split(splitChar)
        For Each line As String In strLine

            MsgBox(day)

        Next


    End If
End Sub
End Class

但它只返回一个数字。如果我将day设置为字符串而不是整数，那么它工作得非常完美，只是它读取整个字符串，而不是我需要的两个整数。请帮忙。我做错了什么

编辑：

输入文件如下所示：

23728 121010 00004986 00 00  2 21 22 11   447 114  2   382   292   350

23730 121010 00064120 00 00 51 19 21 12  1064 110  2  4500   572  7734

For Each line As String In File.ReadAllLines(fileName)
    MessageBox.Show(line)
Next

Dim streamReader As New StreamReader(fileName)
Dim line As String = Nothing
Do
    line = streamReader.ReadLine()
    MessageBox.Show(line)
Loop Until line Is Nothing

Dim streamReader As New StreamReader(fileName)
Dim line As String = Nothing
Do
    line = streamReader.ReadLine()
    Dim parts() As String = line.Split()
    Dim wholeNumber As String = parts(1)
    Dim lastTwo As String = wholeNumber.SubString(wholeNumber.Length - 2)
    MessageBox.Show(lastTwo)
Loop Until line Is Nothing

我希望我的输出是：

10
10

10来自“121010”

您编写的所有代码都可以用更少的行完成，如下所示：

23728 121010 00004986 00 00  2 21 22 11   447 114  2   382   292   350

23730 121010 00064120 00 00 51 19 21 12  1064 110  2  4500   572  7734

For Each line As String In File.ReadAllLines(fileName)
    MessageBox.Show(line)
Next

Dim streamReader As New StreamReader(fileName)
Dim line As String = Nothing
Do
    line = streamReader.ReadLine()
    MessageBox.Show(line)
Loop Until line Is Nothing

Dim streamReader As New StreamReader(fileName)
Dim line As String = Nothing
Do
    line = streamReader.ReadLine()
    Dim parts() As String = line.Split()
    Dim wholeNumber As String = parts(1)
    Dim lastTwo As String = wholeNumber.SubString(wholeNumber.Length - 2)
    MessageBox.Show(lastTwo)
Loop Until line Is Nothing

不过，就像您的示例一样，它一次将整个文件加载到内存中，如果它是一个大文件，则可能会出现问题。如果需要考虑文件的大小，最好一次只读取一行，如下所示：

23728 121010 00004986 00 00  2 21 22 11   447 114  2   382   292   350

23730 121010 00064120 00 00 51 19 21 12  1064 110  2  4500   572  7734

For Each line As String In File.ReadAllLines(fileName)
    MessageBox.Show(line)
Next

Dim streamReader As New StreamReader(fileName)
Dim line As String = Nothing
Do
    line = streamReader.ReadLine()
    MessageBox.Show(line)
Loop Until line Is Nothing

Dim streamReader As New StreamReader(fileName)
Dim line As String = Nothing
Do
    line = streamReader.ReadLine()
    Dim parts() As String = line.Split()
    Dim wholeNumber As String = parts(1)
    Dim lastTwo As String = wholeNumber.SubString(wholeNumber.Length - 2)
    MessageBox.Show(lastTwo)
Loop Until line Is Nothing

但是，问题仍然存在，如何将该行拆分为各个值。如果如您的问题中所示，值之间用空格分隔，则可以使用

line.Split

将该行分隔为其所有值的数组。然后，要获取其中一个值的最后两个字符，只需使用

String.SubString

，如下所示：

23728 121010 00004986 00 00  2 21 22 11   447 114  2   382   292   350

23730 121010 00064120 00 00 51 19 21 12  1064 110  2  4500   572  7734

For Each line As String In File.ReadAllLines(fileName)
    MessageBox.Show(line)
Next

Dim streamReader As New StreamReader(fileName)
Dim line As String = Nothing
Do
    line = streamReader.ReadLine()
    MessageBox.Show(line)
Loop Until line Is Nothing

Dim streamReader As New StreamReader(fileName)
Dim line As String = Nothing
Do
    line = streamReader.ReadLine()
    Dim parts() As String = line.Split()
    Dim wholeNumber As String = parts(1)
    Dim lastTwo As String = wholeNumber.SubString(wholeNumber.Length - 2)
    MessageBox.Show(lastTwo)
Loop Until line Is Nothing

您编写的所有代码都可以用更少的行完成，如下所示：

23728 121010 00004986 00 00  2 21 22 11   447 114  2   382   292   350

23730 121010 00064120 00 00 51 19 21 12  1064 110  2  4500   572  7734

For Each line As String In File.ReadAllLines(fileName)
    MessageBox.Show(line)
Next

Dim streamReader As New StreamReader(fileName)
Dim line As String = Nothing
Do
    line = streamReader.ReadLine()
    MessageBox.Show(line)
Loop Until line Is Nothing

Dim streamReader As New StreamReader(fileName)
Dim line As String = Nothing
Do
    line = streamReader.ReadLine()
    Dim parts() As String = line.Split()
    Dim wholeNumber As String = parts(1)
    Dim lastTwo As String = wholeNumber.SubString(wholeNumber.Length - 2)
    MessageBox.Show(lastTwo)
Loop Until line Is Nothing

23728 121010 00004986 00 00  2 21 22 11   447 114  2   382   292   350

23730 121010 00064120 00 00 51 19 21 12  1064 110  2  4500   572  7734

For Each line As String In File.ReadAllLines(fileName)
    MessageBox.Show(line)
Next

Dim streamReader As New StreamReader(fileName)
Dim line As String = Nothing
Do
    line = streamReader.ReadLine()
    MessageBox.Show(line)
Loop Until line Is Nothing

Dim streamReader As New StreamReader(fileName)
Dim line As String = Nothing
Do
    line = streamReader.ReadLine()
    Dim parts() As String = line.Split()
    Dim wholeNumber As String = parts(1)
    Dim lastTwo As String = wholeNumber.SubString(wholeNumber.Length - 2)
    MessageBox.Show(lastTwo)
Loop Until line Is Nothing

但是，问题仍然存在，如何将该行拆分为各个值。如果如您的问题中所示，值之间用空格分隔，则可以使用

line.Split

将该行分隔为其所有值的数组。然后，要获取其中一个值的最后两个字符，只需使用

String.SubString

，如下所示：

23728 121010 00004986 00 00  2 21 22 11   447 114  2   382   292   350

23730 121010 00064120 00 00 51 19 21 12  1064 110  2  4500   572  7734

For Each line As String In File.ReadAllLines(fileName)
    MessageBox.Show(line)
Next

Dim streamReader As New StreamReader(fileName)
Dim line As String = Nothing
Do
    line = streamReader.ReadLine()
    MessageBox.Show(line)
Loop Until line Is Nothing

Dim streamReader As New StreamReader(fileName)
Dim line As String = Nothing
Do
    line = streamReader.ReadLine()
    Dim parts() As String = line.Split()
    Dim wholeNumber As String = parts(1)
    Dim lastTwo As String = wholeNumber.SubString(wholeNumber.Length - 2)
    MessageBox.Show(lastTwo)
Loop Until line Is Nothing

一些建议：

始终处置资源（使用或尝试使用资源中心（关闭）

永远不要相信用户的输入

编写能够处理足够多不希望出现的情况的代码

基于代码的更正：

 Try
        Dim text As String = Nothing

        Using streamreader As New System.IO.StreamReader("text.txt")
            text = streamreader.ReadToEnd()
        End Using
        If IsNothing(text) = False Then
            Dim strLine() As String = text.Split(New String() {Environment.NewLine}, StringSplitOptions.None)
            For Each line As String In strLine

                If line.Length > 12 Then MsgBox(line.Substring(10, 2))
            Next
        End If
    Catch ex As Exception
        'filenotfound case
    End Try

另一种方式：

在行输入可以不同的情况下（但在我们的情况下，第二个值应该是第二个值）

然后可以使用

Regex

以下是如何：

Try
    Using streamreader As New System.IO.StreamReader(file)
        Dim line As String
        While streamreader.Peek > 0
            'unreaded line from file
            line = streamreader.ReadLine()
            'split input by non digits
            Dim numberstrs As String() = Regex.Split(line, "\D+")
            'second numbers last two
            If numberstrs.Length > 1 AndAlso numberstrs(1).Length > 2 Then
                Console.WriteLine("{0}", numberstrs(1).Substring(numberstrs(1).Length - 2, 2))
            End If

        End While


    End Using
Catch ex As Exception

End Try

一些建议：

始终处置资源（使用或尝试使用资源中心（关闭）

永远不要相信用户的输入

编写能够处理足够多不希望出现的情况的代码

基于代码的更正：

 Try
        Dim text As String = Nothing

        Using streamreader As New System.IO.StreamReader("text.txt")
            text = streamreader.ReadToEnd()
        End Using
        If IsNothing(text) = False Then
            Dim strLine() As String = text.Split(New String() {Environment.NewLine}, StringSplitOptions.None)
            For Each line As String In strLine

                If line.Length > 12 Then MsgBox(line.Substring(10, 2))
            Next
        End If
    Catch ex As Exception
        'filenotfound case
    End Try

另一种方式：

在行输入可以不同的情况下（但在我们的情况下，第二个值应该是第二个值）

然后可以使用

Regex

以下是如何：

Try
    Using streamreader As New System.IO.StreamReader(file)
        Dim line As String
        While streamreader.Peek > 0
            'unreaded line from file
            line = streamreader.ReadLine()
            'split input by non digits
            Dim numberstrs As String() = Regex.Split(line, "\D+")
            'second numbers last two
            If numberstrs.Length > 1 AndAlso numberstrs(1).Length > 2 Then
                Console.WriteLine("{0}", numberstrs(1).Substring(numberstrs(1).Length - 2, 2))
            End If

        End While


    End Using
Catch ex As Exception

End Try

史蒂文的回答让你了解了大部分情况，但不是全部。值得注意的是，您实际上不想要第6个整数，因为它可能是1或2，或者几乎任何东西，这取决于您如何分割它。同样，在你的例子中，你说你想从121010中得到10，这可能是字符串中第二组两个数字或第三组两个数字

我注意到，在您的示例字符串中有一些双空格：您需要对其进行排序以作为开始，否则使用

String.Split

将为您提供数组中的空元素。事实上，使用上面Steven使用的

parts（5）

可以得到一个空元素，这要归功于双空格，而这不是您想要的。您需要

部分（2）

，然后需要

子字符串

来获得所需的数字

另一种更优雅的方法是使用正则表达式来获取数字。假设您想要该字符串中的第二个10（以粗体显示）：12*10*10。如果您知道该字符串将始终为6个字符，将始终是输入行中的第二个字段，并且您始终需要第三个和第四个数字，那么您可以：

Imports System.Text.RegularExpressions
Imports System.IO

Private Sub ReadFile
    Dim rx As New Regex("^[^\s]+\s{1}\d{2}(\d{2}?)", RegexOptions.Compiled Or RegexOptions.CultureInvariant)
    Dim streamReader As New StreamReader(fileName)
    Dim line As String = String.Empty

    Do While streamReader.Peek >= 0
        line = streamReader.ReadLine()
        MessageBox.Show(rx.Matches(line)(0).Groups(1).Value)
    Loop 
End Sub

我并不是说这是唯一（或最优雅）的正则表达式，但它会起作用，意味着您不必使用子字符串，也不在乎第一个字段的长度。它还假定字段之间只有一个空格，但也可以根据需要进行更改。只要你能制定出一个规则来达到你想要的位置，你就可以对它进行正则化。使用Expresso（免费且功能强大的实用程序）帮助您构建合适的表达式

史蒂文的回答让你了解了大部分，但不是全部。值得注意的是，您实际上不想要第6个整数，因为它可能是1或2，或者几乎任何东西，这取决于您如何分割它。同样，在你的例子中，你说你想从121010中得到10，这可能是字符串中第二组两个数字或第三组两个数字

我注意到，在您的示例字符串中有一些双空格：您需要对其进行排序以作为开始，否则使用

String.Split

将为您提供数组中的空元素。事实上，使用上面Steven使用的

parts（5）

可以得到一个空元素，这要归功于双空格，而这不是您想要的。您需要

部分（2）

，然后需要

子字符串

来获得所需的数字

Imports System.Text.RegularExpressions
Imports System.IO

Private Sub ReadFile
    Dim rx As New Regex("^[^\s]+\s{1}\d{2}(\d{2}?)", RegexOptions.Compiled Or RegexOptions.CultureInvariant)
    Dim streamReader As New StreamReader(fileName)
    Dim line As String = String.Empty

    Do While streamReader.Peek >= 0
        line = streamReader.ReadLine()
        MessageBox.Show(rx.Matches(line)(0).Groups(1).Value)
    Loop 
End Sub

我并不是说这是唯一（或最优雅）的正则表达式，但它会起作用，意味着您不必使用子字符串，也不在乎第一个字段的长度。它还假定字段之间只有一个空格，但也可以根据需要进行更改。只要你能制定出一个规则去