VBA Nested Do While Loop vs. Nested Do While If Loop - vba

Question

I'm not sure where I'm going wrong. I'm trying to compare values within a column ("B") to a cell referenced to ("A1"). If the values in Column "B" equal "A1" I want it to count up. When it gets to the end of Column "B" I'm trying to get it to loop back and compare values in column "B" with "A2", etc. For example:
So Far I've written two different codes one with a nested do while loop and a nested do while if loop but i cant get them to loop through the whole column
Sub CountDb()
Dim i As Long
Dim iRow As Long
Dim initial As Long
i = 1
iRow = 1
initial = 1
Do While Cells(iRow, "A").Value <> "" 'initial loop, whilst there are values in cell "A" continue the loop
Do While Cells(i, "B").Value = Cells(iRow, "A").Value 'nested while loop, comparing the first B1 and cell A1.
If True Then Cells(i, "C") = initial 'if they A1 and B1 are equal, print 1 in column C
initial = initial + 1 'and move on comparing A1 with B2
If False Then
i = i + 1 'if not satisfied, move on to cell B2 etc.
Loop
iRow = iRow + 1 'when you get to the end of column B, start again and compare values with A2 and B
Loop
End Sub
Sub CountDb()
Dim i As Long
Dim iRow As Long
Dim initial As Long
'same comments as above, just different methodology
i = 1
iRow = 1
initial = 1
Do While Cells(iRow, "A").Value <> ""
If Cells(i, "B").Value = Cells(iRow, "A").Value Then
Cells(i, "C") = initial
Else
initial = initial + 1
i = i + 1
End If
iRow = iRow + 1
Loop
End Sub
Any help would be appreciated. Thanks!
*EDIT - fixed up column references
**EDIT - applied comments to code

Answer 1

Try this instead:
Option Explicit
Sub test()
Dim sht As Worksheet
Dim lastrow As Long, i as integer, j as integer, initial as integer
Set sht = Workbooks("Book1").Worksheets("Sheet1") 'Don't forget to change this
lastrow = sht.Cells(sht.Rows.Count, "A").End(xlUp).Row
For i = 1 To lastrow
initial = 1
lastrow = sht.Cells(sht.Rows.Count, "B").End(xlUp).Row
For j = 1 To lastrow
If Workbooks("Book1").Worksheets("Sheet1").Range("A" & i).Value = Workbooks("Book1").Worksheets("Sheet1").Range("B" & j).Value Then
Workbooks("Book1").Worksheets("Sheet1").Range("C" & j).Value = initial
initial = initial + 1
End If
Next j
Next i
End Sub
I prefer using For loops as opposed to Whiles, just because I can see the ranges being looped through more easily. Here we use nested For loops, the first to loop through column A, the second to loop through column B. If our value in column A equals our value in column B, we place the initial number in column C using our variable from the nested loop.
Notice how to make this work, we re-initialize our lastrow variable to make the ranges for our loops.

Answer 2

It is useful to use countif.
Sub test()
Dim rngOrg As Range, rngDB As Range
Dim Wf As WorksheetFunction
Dim vR() As Variant
Dim i As Long, n As Long
Set Wf = WorksheetFunction
Set rngOrg = Range("a1", Range("a" & Rows.Count).End(xlUp))
Set rngDB = Range("b1", Range("b" & Rows.Count).End(xlUp))
n = rngDB.Rows.Count
ReDim vR(1 To n, 1 To 1)
For Each Rng In rngDB
i = i + 1
If Wf.CountIf(rngOrg, Rng) Then
vR(i, 1) = Wf.CountIf(Range("b1", Rng), Rng)
End If
Next Rng
Range("c1").Resize(n) = vR
End Sub

Answer 3

Here is another method, this time using Find. This is probably quicker than the looping method since it leverages the in-built find function to skip to the next match.
I've commented the code below for clarity, but basically we loop through values in column A (using a For loop because they're less prone to disguised infinite looping than While) and look for them in column B.
Note: This looks a bit longer, but that's mainly because (a) I've added lots of comments and (b) I've used a With statement to ensure the ranges are fully qualified.
Sub countdb()
Dim c As Range, fnd As Range, listrng As Range, cnt As Long, addr As String
' Use with so that our ranges are fully qualified
With ThisWorkbook.Sheets("Sheet1")
' Define the range to look up in (column B in this case)
Set listrng = .Range("B1", .Range("B1").End(xlDown))
' Loop over values in the index range (column
For Each c In .Range("A1", .Range("A1").End(xlDown))
cnt = 0
' Try and find the c value
Set fnd = listrng.Find(what:=c.Value, lookat:=xlWhole, LookIn:=xlValues, after:=listrng.Cells(listrng.Cells.Count))
If Not fnd Is Nothing Then
' Store the address of the first find so we can stop when we find it again!
addr = fnd.Address
' Loop over all other matches in the range. By using a "Do ... Loop While"
' style loop, we ensure that the loop is run at least once!
Do
' Increase count and assign value to next column
cnt = cnt + 1
fnd.Offset(0, 1).Value = cnt
' Find next match after current
Set fnd = listrng.Find(what:=c.Value, lookat:=xlWhole, LookIn:=xlValues, after:=fnd)
Loop While fnd.Address <> addr
End If
Next c
End With
End Sub

Answer 4

The trick is in making the declarations transparent. After that the programming is very easy.
Sub CountMatches()
Dim Rng As Range ' "count" range (= column "B")
Dim Itm As String ' item from the "items' column (= "A")
Dim Rla As Long, Rlb As Long ' last row in columns A and B
Dim Ra As Long, Rb As Long ' row counters
Dim Counter As Long ' count matches
With ActiveSheet
' look for the last used rows
Rla = .Cells(.Rows.Count, "A").End(xlUp).Row
Rlb = .Cells(.Rows.Count, "B").End(xlUp).Row
' start looking for matches from row 2
Set Rng = .Range(.Cells(2, "B"), .Cells(Rlb, "B"))
' start looping in row 2
For Ra = 2 To Rla
Itm = .Cells(Ra, "A").Value
If Len(Trim(Itm)) Then ' skip if blank
' start comparing from row 2
For Rb = 2 To Rlb
' compare not case sensitive
If StrComp(.Cells(Rb, "B").Value, Itm, vbTextCompare) = 0 Then
Counter = Counter + 1
End If
Next Rb
.Cells(Ra, "C").Value = Counter
Counter = 0
End If
Next Ra
End With
End Sub
Now the question is whether the transparency that workred for me appears transparent to you. I hope it does. :-)

Answer 5

This should be significantly faster.
Sub CountMatches_2()
Dim Rng As Range ' "count" range (= column "B")
Dim Itm As String ' item from the "items' column (= "A")
Dim Rla As Long, Rlb As Long ' last row in columns A and B
Dim Ra As Long, Rb As Long ' row counters
With ActiveSheet
' look for the last used rows
Rla = .Cells(.Rows.Count, "A").End(xlUp).Row
Rlb = .Cells(.Rows.Count, "B").End(xlUp).Row
' start looking for matches from row 2
Set Rng = .Range(.Cells(2, "B"), .Cells(Rlb, "B"))
' start looping in row 2
For Ra = 2 To Rla
Itm = .Cells(Ra, "A").Value
If Len(Trim(Itm)) Then ' skip if blank
.Cells(Ra, "C").Value = Application.CountIf(Rng, Itm)
End If
Next Ra
End With
End Sub
This code presumes that each item in column A is unique. If it is not duplicates will be created which, however, it would be easy to eliminate either before or after they are created.