Creating a ID based on number of appearances in the list above

[vijay]

I have a column which has say the following data:

A
A
B
A
A
A
C
B
B
I want an ID column next to it that will have the following numbers:
Item ID
A 1
A 2
B 1
A 3
A 4
A 5
C 1
B 2
B 3

The ID is based on the sequence for only the item. When A appears first, its ID is 1, and in the next appearance it’s ID is 2 and so on.

Any help is well appreciated. Thanks.

[ThinhDinh]

Do you have an already existing set of data for this, or you want an idea to start building it?

If you have not started, I would advise using a custom form, fill the item input into a user-specific column, make a relation from that usc to the existing item column, count the number of items using a rollup, then use a math column to add 1 to that count, use it as the ID for the next item.

If you have already had the list of items, I would advise using a Google Sheet formula for this.

[AymenM]

Please continue to post your questions under the #help-how-to category, this will help us keep the community well organized. We appreciate your help !

[Lucas_Pires]

Something like this?

Rollup...by rank?

Is there anyway to get the sort order of a list based on value to the maximum? With rollup, I can get the max, avg and min, but I’d love to get the RANK of a list based on these values. Sure, I can sort by the value in an inline list, but i wanted to retrieve the ordinal number of each row in this sorted list. I could always use a spreadsheet formula, but was hoping to avoid it.