EXCEL VBA: looping through columns and copying - vba

Question

In excel I have four columns. There are numbers in the first column, the second column is blank, the third also contains numbers and the fourth contains text.
I want to check each value in the first column and check if it exists in the third column. If it does the value in the fourth column next to the corresponding third column should be copied up to the second column next to the corresponding first column.
I am getting the error compile error. Next without For. Here is my code so far:
Sub Compare()
Dim colA As Integer, colB As Integer
colA = Columns("A:A").Rows.Count
colB = Columns("C:C").Rows.Count
For I = 2 To colA 'loop through column A
For j = 2 To colB 'loop through column C
' If a match is found:
If Worksheets("Sheet1").Cells(I, 1) = Workshee("Sheet1").Cells(j, 3) Then
' Copy
Worksheets("Sheet1").Cells(j, 4) = Worksheets("Sheet1").Cells(I, 2)
'Exit For
Next j
Next I
End Sub

Answer 1

As already pointed out in the comments above you could also accomplish this with a VLookUp or a combination of INDEX/MATCH. Yet, if you wish to stick with VBA then you should adjust your code a bit.
Option Explicit
Sub Compare()
Dim ws As Worksheet
Dim i As Long, j As Long
Dim colA As Long, colC As Long
Set ws = ThisWorkbook.Worksheets("Sheet1")
colA = ws.Cells(ws.Rows.Count, "A").End(xlUp).Row
colC = ws.Cells(ws.Rows.Count, "C").End(xlUp).Row
'loop through column A
For i = 2 To colA
'loop through column C
For j = 2 To colC
' If a match is found:
If ws.Cells(i, 1).Value2 = ws.Cells(j, 3).Value2 Then
' Copy column B to Column D as written in your code above
ws.Cells(j, 4).Value2 = ws.Cells(i, 2).Value2
' or copy column D to Column B as written in the question / post
ws.Cells(i, 2).Value2 = ws.Cells(j, 4).Value2
'Exit For
End If
Next j
Next i
ws.Range("D2:D" & colC).FormulaR1C1 = "=INDEX(R2C2:R" & colA & "C2,MATCH(RC[-1],R2C1:R" & colA & "C1,0))"
End Sub
The above code will do both:
the VBA way and
write the INDEX/MATCH formulas for you.
Just delete the code segment you don't want.

Answer 2

If you insist on using your code, then use this fixed version. It should work fine though it's untested.
Sub Compare()
Dim LastRowA As Long, LastRowB As Long, i As Long, j As Long
With Worksheets("Sheet1")
LastRowA = .Range("A" & Rows.Count).End(xlUp).Row
LastRowC = .Range("C" & Rows.Count).End(xlUp).Row
For i = 2 To LastRowA
For j = 2 To LastRowC
If .Cells(i, 1) = .Cells(j, 3) Then .Cells(i, 2) = .Cells(j, 4): Exit For
Next j
Next i
End With
End Sub
Let me know in the comment section if there's any error.