Organizing a large data set (looking for duplicates)

Hey All,

I have a large-ish data set (about 10,000 rows). I am looking to identify duplicates in two columns and subsequently align the items with duplicates to a few data points. For example, in the attached file, I am looking to identify all of the items in "column B" of Tab_1 that have a duplicate in "column A" of the same tab. For those that have a duplicate, I would like to identify all of the "instances" and colours" associated with each animal.

Some assumptions:
- The items in Column A do not necessarily have a duplicate in Column B and vice-versa
- The "instances" aren't unique IDs (another "instance 1" could appear further down in the data)

I think the solution would be something like an array "if" formula, but I'm drawing a blank right now. If someone has any ideas, it would be much appreciated.

Thanks,
B

Excel_Help8.xlsx

How do you want this organized? And are you familiar with UDFs?

I made your book macro-enabled and added the "=ARLOOKUP" UDF. Is this what you have in mind?

Hey All,

Sorry about the late reply. Hoyasaxa215, your attached file is exactly the example I was looking for. The Column "D" in particular that only shows the unique list was very helpful. Granted with the size of the tab I was working with it basically crashed my poor old laptop.

Thanks,
Blake