I have two columns in my Sheet, one labeled serial number and the other category.
The serial number for each item is based on its category as well as its order in the table, and is numbered using a sequence starting from 1 and incrementing by 1 for each additional item.
Each category uses its own number sequence, so a
serial number would be unique within a category, but there would be duplicated numbers between different categories.
I can't figure out how to create an array formula to generate the serial number
Sample Desired Result
| serial number | category | item |
|---|---|---|
| 1 | cat_1 | txt_string |
| 2 | cat_1 | txt_string |
| 1 | cat_2 | txt_string |
| 3 | cat_1 | txt_string |
| 4 | cat_1 | txt_string |
| 2 | cat_2 | txt_string |
| 3 | cat_2 | txt_string |
| 1 | cat_3 | txt_string |
