Conditional Formats for Odd and Even Columns

Zar has a need to apply a conditional format to the values in column A of a worksheet, but he can't figure out what the rules might be. Besides column A, he also has data starting in column B and he periodically adds new columns of data. If there is data in all the odd columns starting with B, Zar wants one format applied in column A. (B is data column 1 for his worksheet, so he considers it odd.) If there is data in all the even columns beginning with C, Zar wants a different format applied in column A. If there is data in all the data columns starting with B—however many that might be—then he wants a third format applied.

As Zar has no doubt figured out, you can easily create a formula to determine whether there is information in columns B and C and apply formatting accordingly. In fact, a simple formula such as these will do the trick:

=COUNTA(B1:C1)=2
=COUNTA(B1)=1
=COUNTA(C1)=1

The first formula returns True if there is information in both B and C, the second if there is information in B, and the third if there is information in C. As long as you select "Stop If True" for each rule/formula, then your formatting will work fine.

Creating a formula for multiple columns beyond B and C is only marginally more difficult. The same three types of formulas, in order, would be as follows:

=COUNTA(B1:G1)=6)
=COUNTA(B1,D1,F1)=3
=COUNTA(C1,E1,G1)=3

You could easily add additional cell references to the formulas, as needed. Such an approach returns True in only three conditions: if ALL cells in the range B1:G1 have something in them, if ALL odd cells (B1, D1, F1) have something in them, and if ALL even cells (C1, E1, G1) have something in them. It won't return True if only some of the cells in the range have values in them. For instance, there are values in cells B1, C1, and E1, then it won't return True and none of the criteria for formatting will be met.

While these all work fine with the noted limitation, they aren't exactly what Zar is looking for—he wants a formula that will detect how many columns are being used week after week, as he continues to add data to columns, and adjust the formula accordingly without the need to manually edit the formula to take into account the added data. In other words, if he adds data to column H, he would want the formulas to automatically be adjusted to take into account the added column:

=COUNTA(B1:H1)=7)
=COUNTA(B1,D1,F1,H1)=4
=COUNTA(C1,E1,G1)=3

That is obviously a more complex need. Perhaps the best way to approach the problem is to create a user-defined function (a macro) that can look at a range of cells and determine if one of the three criteria are met. Consider the following macro:

Function CellChk(crng As Range) As String
    Dim iNumOdds As Integer
    Dim iNumEvens As Integer
    Dim iOdds As Integer
    Dim iEvens As Integer
    Dim iTots As Integer
    Dim iTotCells As Integer
    Dim rWork As Range
    Dim rCell As Range
    Dim iLastCol As Integer
    Dim sTemp As String

    iOdds = 0
    iEvens = 0
    iTots = 0

    ' Figure out the real last column in the worksheet and set range
    iLastCol = ActiveSheet.Cells.Find(What:="*", _
        SearchOrder:=xlByColumns, SearchDirection:=xlPrevious, _
        LookIn:=xlFormulas).Column
    Set rWork = Range(Cells(crng.Row, 2), Cells(crng.Row, iLastCol))

    iTotCells = rWork.Count
    iNumOdds = (iTotCells + 1) \ 2    ' Number of odd columns
    iNumEvens = iTotCells - iNumOdds  ' Number of even columns

    For Each rCell In rWork
        If rCell <> "" Then
            If ((rCell.Column - 1) Mod 2) = 1 Then
                iOdds = iOdds + 1
            Else
                iEvens = iEvens + 1
            End If
            iTots = iTots + 1
        End If
    Next rCell

    sTemp = ""
    If iTots = iTotCells Then
        sTemp = "t"
    ElseIf iOdds = iNumOdds Then
        sTemp = "o"
    ElseIf iEvens = iNumEvens Then
        sTemp = "e"
    End If
    CellChk = sTemp
End Function

You use the macro by passing it an address in the row you want to check. So, for instance, if you were applying the conditional formatting rule to cell A3, you would pass the macro an address of B3 or C3—anything except A3, as that will cause a circular reference. The macro looks for the last cell used in that row and then determines how many odd and even cells have something in them. The macro returns any of four values; if the first criteria is met (all cells in the row starting with column B have something in them) then a "t" is returned. If all the odd columns (with B being the first odd column) have something in them, then "o" is returned. If all the even columns (with C being the first even column) have something in them, then "e" is returned. If none of the three criteria are met, then the function returns nothing.

You'll still need to set up three conditional formatting rules that rely on the evaluation of a formula. Here are three you can use with this macro:

=CellChk(B1)="t")
=CellChk(B1)="o")
=CellChk(B1)="e")

These examples are for applying a conditional format to cell A1; adjust the cell references to the correct row that you want the macro to analyze. Remember that even though you specify a single cell (B1 in these examples), the macro calculates how many cells in the row to actually look at.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (5945) applies to Microsoft Excel 2007, 2010, 2013, 2016, 2019, and Excel in Microsoft 365.