Gibt es eine bessere Implementierung für die String-Funktion MID oder gibt es einen besseren Implementierungsstil für VBA, der schneller ist

Question

Ich habe Skript, das 'MID' (16N) mal aufruft und es dauert etwa 4 Minuten, wenn N = 43 ausgeführt wird . ich bin nicht sicher, warum es so lange dauert es einen String von ~ 440 Zeichen ist jedes Mal aufrufen:

Sub Button1_Click() 
If Sheets.count = 1 Then 
a = ActiveWorkbook.Name  
ChDir "C:\" 
MsgBox "Be Prepared to a text file", vbExclamation, _ 
Application.ScreenUpdating = False 
Application.Calculation = xlCalculationManual 
FileToOpen = Application.GetOpenFilename("Text Files (*.txt), *.txt") 
Workbooks.OpenText FileToOpen, Origin:=xlWindows, _ 
    StartRow:=1, DataType:=xlDelimited, Tab:=True 
x = ActiveWorkbook.Name  'SO # workbook 
Workbooks(x).Sheets(1).Copy after:=Workbooks(a).Sheets(1) 
ActiveSheet.Name = "Results" 
Windows(x).Activate   'SO # workbook 
ActiveWorkbook.Close 
'I also need to declare the value of each column with each 'with' statement 
Range("A1").Select 
With Rows("1:1") 
.Insert Shift:=xlDown 
End With 
With Range("A1")  
.Font.Bold = True 
End With 
'Columns("A:A").EntireColumn.AutoFit 
With Range("B1") 
.Font.Bold = True 
End With 
Columns("B:B").EntireColumn.AutoFit 
With Range("C1")  
.Font.Bold = True 
End With 
Columns("C:C").EntireColumn.AutoFit 
With Range("D1") 
.Font.Bold = True 
End With 
Columns("D:D").EntireColumn.AutoFit 
With Range("E1") 
.Font.Bold = True 
End With 
Columns("E:E").EntireColumn.AutoFit 
With Range("F1")  
.Font.Bold = True 
End With 
Columns("F:F").EntireColumn.AutoFit 
With Range("G1")  
.Font.Bold = True 
End With 
Columns("G:G").EntireColumn.AutoFit  
With Range("H1")  
.Font.Bold = True 
End With  
Columns("H:H").EntireColumn.AutoFit  
With Range("I1")  
.Font.Bold = True 
End With 
Columns("I:I").HorizontalAlignment = xlLeft 
Columns("I:I").EntireColumn.AutoFit 
With Range("J1")  
.Font.Bold = True 
End With 
Columns("J:J").EntireColumn.AutoFit 
With Range("K1")  
.Font.Bold = True 
End With 
Columns("K:K").EntireColumn.AutoFit 
With Range("L1")  
.Font.Bold = True 
End With 
Columns("L:L").EntireColumn.AutoFit 
With Range("M1")  
.Font.Bold = True 
End With 
Columns("M:M").EntireColumn.AutoFit  
With Range("N1")  
.Font.Bold = True 
End With  
Columns("N:N").EntireColumn.AutoFit 
With Range("O1")  
.Font.Bold = True 
End With  
Columns("O:O").EntireColumn.AutoFit 
With Range("P1")  
End With  
Selection.Font.Bold = True 
Columns("P:P").EntireColumn.AutoFit  
With Range("Q1") 
.Font.Bold = True 
End With 
Columns("Q:Q").EntireColumn.AutoFit 
Dim i As Long 
Dim current As String 
'Dim Strings As Variant 
Dim count As Integer 
Dim cell As Integer 
Set rng = Range(Cells(1, 1), Cells(Rows.count, 16))  
For i = 2 To Rows.count 'foreach row 
    current = Cells(i, 1).Value 
    cell = 0 '0 
    rng(i, cell + 1).Value = Mid(current, 3, 7) 
    cell = cell + 1 
    rng(i, cell + 1).Value = Mid(current, 9, 7) 
    cell = cell + 1 
    rng(i, cell + 1).Value = Mid(current, 16, 5) 
    cell = cell + 1 
    rng(i, cell + 1).Value = Mid(current, 40, 10) 
    cell = cell + 1 
    rng(i, cell + 1).Value = Mid(current, 50, 8) 
    cell = cell + 1 
    rng(i, cell + 1).Value = Mid(current, 58, 8) 
    cell = cell + 1 
    rng(i, cell + 1).Value = Mid(current, 66, 4) 
    cell = cell + 1 
    rng(i, cell + 1).Value = Mid(current, 70, 2) 
    cell = cell + 1 
    rng(i, cell + 1).Value = Mid(current, 100, 20) 
    cell = cell + 1 
    rng(i, cell + 1).Value = Mid(current, 120, 6) 
    cell = cell + 1 
    rng(i, cell + 1).Value = Mid(current, 126, 10) 
    cell = cell + 1 
    rng(i, cell + 1).Value = Mid(current, 136, 10) 
    cell = cell + 1 
    rng(i, cell + 1).Value = Mid(current, 146, 12) 
    cell = cell + 1 
    rng(i, cell + 1).Value = Mid(current, 158, 12) 
    cell = cell + 1 
    rng(i, cell + 1).Value = Mid(current, 170, 12) 
    cell = cell + 1 
    rng(i, cell + 1).Value = Mid(current, 194, 255) 
    cell = cell + 1 
    rng(i, cell + 1).Value = Mid(current, 449, 255) 
    cell = cell + 1 
Next i 
ActiveSheet.ListObjects.Add(xlSrcRange, Range(rng(1, 1), rng(Rows.count, cell)), , xlYes).Name = _ 
    "Table1" 
ActiveSheet.ListObjects("Table1").TableStyle = "TableStyleLight2" 
Application.ScreenUpdating = True 
MsgBox "Macro has finished running" 
MsgBox "Data is now in Excel format and can be saved to a new file.", _ 
vbExclamation, "MORE CHOICES" 
Application.Calculation = xlCalculationAutomatic 
Else 
    MsgBox "Additional tab already exists. Only MACROS tab should exist in  workbook prior to running macro.", _ 
vbExclamation, "** Additional tab already exists **" 
End If 
End Sub 

ich habe für this Quelle als Referenz wurde mit der Zeit es braucht, um zu versuchen, zu reduzieren.

Irgendwelche Ideen?

Answer 1

In dem Direkt-Fenster (Strg + G), Typ:

? Rows.Count 
1048576 

, dass die Anzahl der Zeilen ist Sie Looping.

Wo auch immer Sie Rows.Count verwendet, diese stattdessen verwenden:

ActiveSheet.UsedRange.Rows.Count 

oder dass numRows und verwendet, die auf einen lange Variablen zuweisen.

Debugging VBA Code hätte dazu beigetragen, das Problem zu finden, mit einem Haltepunkt in der Schleife.

Answer 2

Nein, ist es nicht eine besser Umsetzung jedoch sollten Sie sich bewusst sein, dass Mid() gibt einen Variant und Ihr Code verwendet dann implizite Umwandlung der String Version zurückzukehren.

Wenn Sie die Zeichenfolge-Version dieser Funktion verwenden: Mid$()(man beachte das Dollarzeichen) dann der Rückgabetyp ist explizite und immer als String zurückgegeben. Diese kann marginal schneller in hohen Wiederholungen des Codes sein.