Identify blocks of the same value in a sequence with unique identifier

[dgerding]

Hi all -

I'm trying to randomly generate a unique identifier for each block of the same value in a column. In my mind, it's something that searches for "groups" or "blocks" of records in column A and then assigned a sequential identifier in column B. I'm not picky about the identifier, I just need each "block" to be unique.

Is this possible without writing a macro? I've attached an example below. I have over 40,000 rows so I really need to automate this process. Thanks in advance!

Value	Unique Sequence Identifier
YES	1
YES	1
YES	1
NO	2
NO	2
NO	2
NO	2
NO	2
NO	2
NO	2
NO	2
NO	2
YES	3
YES	3
YES	3
YES	3
YES	3
YES	3
YES	3
NO	4
NO	4
NO	4
NO	4

<colgroup><col><col></colgroup><tbody>
</tbody>

 

[pbornemeier]

Welcome to the Board!

If you put a 1 in B2, then put this formula in B3 and copy it down you will get what you are asking for:

=IF(A3=A2,B2,B2+1)

 

[dgerding]

This is perfect - and so simple! Thanks!