Duplication in Column

[ionelz]

Column A - Column B - Column C
123 --------A1
123---------A1-------------I
123---------B1
567---------A1
567---------B1
567---------C1
567---------A1-------------I

If, per Number in Column A, in Column B are DUPLICATION, then assign in Column C, "I" beginning second appearance
For 123, A1 appear 2 times
For 567, A1 appear 2 times

[dosydos]

I don't quite understand what you are asking for when looking at your make shift graph. Please attach a sample worksheet showing what you are requesting. Thanks

[6StringJazzer]

Put this formula in C1 and copy down:

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[ionelz]

Thank you, got it !

[ionelz]

Why do I get this error ? Attached

Formula omits adjacent cells
Update to formula to include cells
If I sort B, some error disappear
If I sort A, they are back

[6StringJazzer]

I don't see any errors in that file.

[ionelz]

For some reason I get it

[dosydos]

In this case that is not an error, but more of a warning alerting you that the formula omits adjacent cells. I believe 6Strings formula is working correctly so you should just ignore the warning.

[ionelz]

Formula works in 2013 excel but I got this error, but I get other errors.
I just updated from 2013 to Office 365 Pro Plus.
Can this formula be written in another way ?

[6StringJazzer]

This is the simplest way to get the result you want. I suppose it could also be done with a somewhat more complex SUMPRODUCT formula or even an array formula but I would guess that would give you the same "error".

There are some situations where Excel is over-aggressive about identifying as an error. The error you are getting is, in my opinion, useless. I have Excel configured to ignore that warning.

errorcheckingoptions.jpg

[ionelz]

Yes, formula is ok.
Errors drive me crazy...
Sort one column, error dissapear, sort other column, error come back
I had to turn them off