如何按行分割字符串
编号：QA001860
建立日期: 1999年10月14日 最后修改日期：1999年10月14日
所属类别：
509:
我用VB5读取一个文本文件，由于需逐行读取再分析计算。可是这种读入文件速度对大文件时特别慢。能否把所有文件信息全部读入缓冲区，再处理。可是又如何保证每行每行地分析数据呢。
回答:
先使用Get语句将文件读到一个字符串中，然后，使用Split函数进行逐行的分解。之所以使用Get语句，而不使用Input函数，请参考QA000051 "VB 5提示错误："输入超出文件尾""。下面是一个示例。
Private Sub Command1_Click()
Dim s As String
s = String(FileLen("c:\a.txt"), " ")
Open "c:\a.txt" For Binary As 1
Get #1, , s
Close 1
v = Split(s, vbCrLf)
Dim i
For i = 0 To UBound(v)
List1.AddItem v(i)
Next
End Sub
Public Function Split(ByVal sIn As String, Optional sDelim As _
String, Optional nLimit As Long = -1, Optional bCompare As _
VbCompareMethod = vbBinaryCompare) As Variant
Dim sRead As String, sOut() As String, nC As Integer
If sDelim = "" Then
Split = sIn
End If
sRead = ReadUntil(sIn, sDelim, bCompare)
Do
ReDim Preserve sOut(nC)
sOut(nC) = sRead
nC = nC + 1
If nLimit <> -1 And nC >= nLimit Then Exit Do
sRead = ReadUntil(sIn, sDelim)
Loop While InStr(1, sIn, sDelim, bCompare) > 0
ReDim Preserve sOut(nC)
sOut(nC) = sIn
Split = sOut
End Function
Public Function ReadUntil(ByRef sIn As String, _
sDelim As String, Optional bCompare As VbCompareMethod _
= vbBinaryCompare) As String
Dim nPos As String
nPos = InStr(1, sIn, sDelim, bCompare)
If nPos > 0 Then
ReadUntil = Left(sIn, nPos - 1)
sIn = Mid(sIn, nPos + Len(sDelim))
End If
End Function
此问题由李海回答。
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