Finding Matching Values Within Arrays in VBA - excel

Question

Pretty basic question here but my VBA skills are pretty rusty. I have two worksheets where a machine just dumps data into them. Each sheet is just one column and SheetA has ~250 rows and SheetB has ~1300 rows. So what I need to do is compare the first value in sheetA to every value in sheetB, if a match is found I need to copy it to another sheet (SheetC) and then move to the next value in SheetA and repeat this till every value in SheetA has been compared to every value in SheetB. I think the best way to do this is with arrays but I cannot for the life of me remember how to do the actual comparison. Below is the code calling up the sheets and arrays I think....any help is appreciated!
Dim SheetA As Variant
Dim SheetB As Variant
Dim RangeToCheckA As String
Dim RangeToCheckB As String
'Get the worksheets from the workbooks
Set wbkA = Workbooks.Open(Filename:="H:\Chelsea QE\CD6\Evan West\OSM37 with locations 9-30-19.xls")
Set SheetA = wbkA.Worksheets("OSM37")
Set wbkB = Workbooks.Open(Filename:="H:\Chelsea QE\CD6\Evan West\New folder\Flat Rock and Roush VIN Tracker U625 - U611 Lower control arm welds.xlsx")
Set SheetB = wbkB.Worksheets("Master VIN")
'This is the range in SheetA
RangeToCheckA = "B2:B239"
'This is the range in SheetB
RangeToCheckB = "B4:B1339"
SheetA = SheetA.Range(RangeToCheckA)
SheetB = SheetB.Range(RangeToCheckB)

Answer 1

Without changing much of your code and adding a call to a custom function, you could do the following:
Private Sub CompareWorkBooks()
Dim wbkA As Workbook, wbkB As Workbook
Dim SheetA As Worksheet, SheetB As Worksheet, SheetC As Worksheet
Dim RangeToCheckA As String
Dim RangeToCheckB As String
Dim arrySheetA() As Variant, arrySheetB() As Variant, _
arryOut() As Variant
'Get the worksheets from the workbooks
Set wbkA = Workbooks.Open(Filename:="H:\Chelsea QE\CD6\Evan West\OSM37 with locations 9-30-19.xls")
Set SheetA = wbkA.Worksheets("OSM37")
Set wbkB = Workbooks.Open(Filename:="H:\Chelsea QE\CD6\Evan West\New folder\Flat Rock and Roush VIN Tracker U625 - U611 Lower control arm welds.xlsx")
Set SheetB = wbkB.Worksheets("Master VIN")
'This is the range in SheetA
RangeToCheckA = "B2:B239"
'This is the range in SheetB
RangeToCheckB = "B4:B1339"
'Value 2 is faster as it doesn't copy formatting
arrySheetA() = SheetA.Range(RangeToCheckA).Value2
arrySheetB() = SheetB.Range(RangeToCheckB).Value2
Set SheetC = wbkB.Worksheets("Sheet C")
arryOut() = FastLookUp(arrySheetA, arrySheetB, 1, 1, 1)
SheetC.Range("A1").Resize(UBound(arryOut, 1), _
UBound(arryOut, 2)).Value = arryOut
End Sub
FastLookUp Function:
Private Function FastLookUp(ByRef arryLookUpVals As Variant, ByRef arryLookUpTable As Variant, _
ByVal lngLookUpValCol As Long, ByVal lngSearchCol As Long, _
ByVal lngReturnCol As Long, _
Optional ByVal boolBinaryCompare As Boolean = True) As Variant
Dim i As Long
Dim dictLooUpTblData As Object
Dim varKey As Variant
Dim arryOut() As Variant
Set dictLooUpTblData = CreateObject("Scripting.Dictionary")
If boolBinaryCompare Then
dictLooUpTblData.CompareMode = vbBinaryCompare
Else
dictLooUpTblData.CompareMode = vbTextCompare
End If
'add lookup table's lookup column to
'dictionary
For i = LBound(arryLookUpTable, 1) To UBound(arryLookUpTable, 1)
varKey = Trim(arryLookUpTable(i, lngSearchCol))
If Not dictLooUpTblData.Exists(varKey) Then
'this is called a silent add with is faster
'than the standard dictionary.Add Key,Item
'method
dictLooUpTblData(varKey) = arryLookUpTable(i, lngReturnCol)
End If
varKey = Empty
Next i
i = 0: varKey = Empty
ReDim arryOut(1 To UBound(arryLookUpVals, 1), 1 To 1)
For i = LBound(arryLookUpVals, 1) To UBound(arryLookUpVals, 1)
varKey = Trim(arryLookUpVals(i, lngLookUpValCol))
'if the lookup value exists in the dictionary
'at this index of the array, then return
'its correspoding item
If dictLooUpTblData.Exists(varKey) Then
arryOut(i, 1) = dictLooUpTblData.Item(varKey)
End If
varKey = Empty
Next i
FastLookUp = arryOut
End Function
FastLookup functions exactly like a VLOOKUP, but is a bit more flexible, because the the lookup column does not have to be the first one in the range you are looking up, as you are allowed to specify which column by providing a value for lngLookUpValCol parameter.

Answer 2

Concerning that you have 3 worksheets in 1 workbook - Worksheets(1) and Worksheets(2) are the one, in which the values in Range("A1:A7") and Range("A1:A3") are compared:
Sub TestMe()
Dim arrA As Variant
Dim arrB As Variant
With Application
arrA = .Transpose(Worksheets(1).Range("A1:A7"))
arrB = .Transpose(Worksheets(2).Range("A1:A3"))
End With
Dim a As Variant
Dim b As Variant
For Each a In arrA
For Each b In arrB
If a = b Then
Worksheets(3).Cells(1 + LastRow(Worksheets(3).Name), 1) = b
End If
Next
Next
End Sub
Function LastRow(wsName As String, Optional columnToCheck As Long = 1) As Long
Dim ws As Worksheet
Set ws = Worksheets(wsName)
LastRow = ws.Cells(ws.Rows.Count, columnToCheck).End(xlUp).Row
End Function
If you are planning to use the code above, it is a good idea to make sure that the values in Worksheets(1) are all unique, otherwise the code would repeat them N times. Or add a dictionary, to exclude repeated values.