Question

我想阅读固定长度的文件如果我知道场长，我知道怎么做。

 Using Reader As New Microsoft.VisualBasic.FileIO.TextFieldParser(filePath)

        Reader.TextFieldType =
        Microsoft.VisualBasic.FileIO.FieldType.FixedWidth
        Reader.SetFieldWidths(8, 16, 16, 12, 14, 16) 'They are different in each file

        Dim currentRow As String()
        While Not Reader.EndOfData
            Try
                currentRow = Reader.ReadFields()
                Dim currentField As String
                For Each currentField In currentRow
                    MsgBox(currentField)
                Next
            Catch ex As Microsoft.VisualBasic.
                        FileIO.MalformedLineException
                MsgBox("Line " & ex.Message &
                "is not valid and will be skipped.")
            End Try
        End While
    End Using

问题在于我不知道每个领域的长度有没有办法读取第一行并获得字段长度？

Answer 1

由于我找到了答案，我将在此处发布，以防有人遇到同样的问题。
我用正则表达式解决了它

'sRowData is the first line of the file
 Dim pArLengths() As Integer = Nothing 'Array to store the lengths

 Dim regex As New Regex("[^\W_\d]+", _
                        RegexOptions.IgnoreCase _
                        Or RegexOptions.Multiline _
                        Or RegexOptions.Singleline _
                        Or RegexOptions.IgnorePatternWhitespace)

 Dim myMatches As MatchCollection = regex.Matches(sRowData)

 ReDim pArLengths(myMatches.Count - 1)

 For i = 0 To myMatches.Count - 1
     Dim k As Integer
     k = If(i < myMatches.Count - 1, myMatches(i + 1).Index, sRowData.Length)
     pArLengths(i) = k - myMatches(i).Index
 Next

我希望有人能发现它有用。

提取字段长度

1 个答案: