Excel Tip: Merry Christmas with a quick macro to swap one colour for another

First of all I would like to wish all of my readers and subscribers, a very Merry Christmas and a Happy 2016.

I know we all work hard, and I hope, like me, you all get a chance to spend some time with those you love in the coming days, whether Christmas is a festival you celebrate or not.

One hassle I sometimes have when building spreadsheets for others is changing colours.

The spreadsheet may work perfectly, but the end user might not like the colours I have chosen. This isn't too much of a problem if we are talking about large blocks of colour, but it can be a time-taking process, if I have used yellow to denote input cells throughout the whole worksheet, and the client wants orange, for example!

When this happened recently on a particularly complex spreadsheet, I decided to write a little macro to help, which turned out to be pretty straightforward and does the job in seconds.

Here is the code of the macro.

Sub ColourSwap() 

Dim Source As Variant
Dim R As Integer
Dim G As Integer
Dim B As Integer
Dim NewColour As Variant
Source = ActiveCell.Interior.Color
If MsgBox("Switch to no colour?", vbYesNo) = vbYes Then
NewColour = 0
For Each cell In ActiveSheet.Cells
If cell.Interior.Color = Source Then cell.Interior.ColorIndex = NewColour
Next
Else
R = InputBox("R?")
G = InputBox("G?")
B = InputBox("B?")
NewColour = RGB(R, G, B)
For Each cell In ActiveSheet.UsedRange.Cells
If cell.Interior.Color = Source Then cell.Interior.Color = NewColour
Next
End If 

End Sub

The easiest way to include it in your spreadsheet is to hit Alt-F8 and type the name you want to call the macro in the box at the top of the dialog. I have called it ColourSwap. Click create and you will see the green sections above already showing in the window (with your chosen name replacing ColourSwap). Just paste the yellow section in between.

You can run the macro by hitting Alt-F8 again, selecting it and choosing Run. If you prefer, you can click options instead of Run, and assign a shortcut key to run it in future.

The macro works as follows, and is applied to a single worksheet at a time.

1. Click on one of the cells that contain the colour that you wish to swap;
2. Run the Macro
3. You will be asked if you wish to "Switch to no colour?", if you select "Yes", then all of the cells on that worksheet that are the same colour as the cell you selected, will have any Fill Colour removed. This is the same as choosing No Fill if you were colouring the cell manually.
4. If you select "No", you will be faced with 3 prompts, requesting the R, G and B values for the colour you wish to swap to. Once you enter these, all of the cells on the worksheet that are the same colour as the cell you selected, will be filled with this new colour.

NB: The macro only checks the Used Range of the worksheet, so will not change any coloured cells below, or to the right of the last populated cell on the worksheet. This is to save time, as it can take quite a while to loop through every cell, when this is not necessary. If (for some reason) you have coloured cells outside of the Used Range, then these should be very easy to change manually, as they will almost certainly be in a large block.

Note that if you wish to save the Macro with the spreadsheet, you will need to save the Workbook as Macro-enabled Workbook, however this will usually be unnecessary, as once the colours have been changed, the macro is no longer needed, so that you can let it save without the macro.

I hope you find this useful, and could maybe use it to make some tired old spreadsheets look a bit more festive!

Merry Christmas!

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Excel Tip: How many calendar months does a date range affect?

This week I responded to a client request for a formula that seemed straight-forward, but it took a few emails backwards and forwards to establish exactly what was required.

My answers at each stage, provide a number of alternative versions of what appear to be the same thing - but aren't!

The question itself was essentially "How do I calculate the number of months between two dates?"

My first response to this question used the DATEDIF function as featured in this earlier post.

Assuming that the start date is in cell A1 and the end date is in cell A2, then:

=DATEDIF(A1,A2,"M")

will return the number of WHOLE months between the two dates.

My client then said that they wanted to always round up the number of months.

I then used the "MD" argument of a DATEDIF to identify the remaining days after calculating the whole months, so that I could use and IF statement to add 1 if this remainder was greater than zero:

=DATEDIF(A1,A2,"M")+IF(DATEDIF(A1,A2,"MD")>0,1,0)

Finally, it transpired that what was really required was the number of calendar months touched by the date range, e.g. if the start date was 31st January 2015 and the end date was 1st February 2015, the answer should be 2, as both January and February feature in the date range (with the same dates, our first example would return zero, as there are no whole months and our second would have returned 1, as we rounded the 2 days up to a whole month).

This required a completely different approach, by using the month function to pull out the month from each date, and the year function to pull out the year. The answer would then be the difference between the month numbers, plus 1, plus 12 * the difference in the years, i.e.

=(MONTH(A2)-MONTH(A1)+1)+((YEAR(A2)-YEAR(A1))*12)

Depending upon your specific needs, any one of these formulae might be correct for your requirement!

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