Question

我正在创建一个程序来创建一个格式如下的文本文件：

[1，* John，Doe，Family，0002354561]

[2，* Jason，Doe，Obstetric，0002358411]

[3，* Mikael，Doe，Pediatric，0002352361]

[4，* Jamiel，Doe，Orthopedic，0002354547]

我需要的是一种读取文件并获取最后一行的第一个数字的方法。然后把它放到一个整数。

我知道我可以这样读第一行：

    Dim fileReader As System.IO.StreamReader
    fileReader =
    My.Computer.FileSystem.OpenTextFileReader(("..\..\..\Patients.txt"))

    Dim stringReader As String
    stringReader = fileReader.ReadLine()
    MsgBox("The first line of the file is " & stringReader)

但是我如何读取最后一行并将第二个字符串转换为整数变量？

Answer 1

我正在使用类似的东西

Dim lastLine As String = File.ReadLines(myFileName) _
                                .Where(Function(f As String) (Not String.IsNullOrEmpty(f))).Last.ToString
Dim startpos As Integer = lastLine.IndexOf(",", 3)
lastline = Substring(lastline, startpos).Trim
Dim firstchar as String = Substring(lastline,0,1)
Dim result As Integer
    If Integer.TryParse(firstchar, result) Then Return result _
        Else Return -1

Answer 2

以下是如何完成任务的示例，这会将所有数字放入arraylist中。不是通过将其转换为长（或整数），它将删除任何前导零

Public Function GetDigits() As System.Collections.ArrayList
    Dim numList As System.Collections.ArrayList
    numList = New System.Collections.ArrayList()
    Dim fileReader As System.IO.StreamReader
    fileReader = My.Computer.FileSystem.OpenTextFileReader(("C:\Patients.txt"))

    Dim stringReader As String
    While Not fileReader.EndOfStream
        stringReader = fileReader.ReadLine()
        If Trim(stringReader) = "" Then Continue While
        Dim strParts
        strParts = Split(stringReader, Chr(44))
        Try
            numList.Add(Integer.Parse(Trim(Replace(strParts(UBound(strParts)), "]", ""))))
        Catch
            MsgBox("Could not parse string: " & stringReader)
        End Try
    End While
    fileReader.Close()
    GetDigits = numList
End Function

找到文本文件最后一行的第一个数字，并放入整数变量visual basic

2 个答案: