data validation to only allow duplicate if it is in the cell above

[Rodger]

Hi all,

This seems to easy, but I can't get it to work.
I would like to prevent duplicates in a column, unless it is in the cell directly above.
So, in essence, you can enter the same text twice, or more, so long as they are
grouped together.

I am trying something like

=AND(A10<>A9,COUNTIF($A$1:$A$100,A10)=1)

but no luck

any thoughts?

 

[Nebu]

Hi:

May be something like the attached.

Thanks

 

[Rodger]

Hi Nebu,
Sorry, I was looking for data validation to not allow a duplicate, unless it is the same value as the cell above.

Thanks for looking !

 

[Nebu]

Hi:

It would be beneficial if you could upload a sample file so that we don't have to recreate what you are looking for.

Thanks

 

[GraH - Guido]

perhaps it is like this (datavalidation in cell A2, and drag down)
=OR(A1=A2,AND(A1<>A2,COUNTIF($A$1:$A2,A2)=1))

 

[Rodger]

Hi Guido,

Bingo! thats it.
Thank you so much

Cheers !