Hide or delete rows with non-duplicate, unique values in the first column

[gideonfell]

I have a spreadsheet with content IDs in the first column.

I want to analyze the rows with duplicate (not unique) content IDs. The other columns are not the same so the rows are not exact duplicates.

I need a formula or macro that will hide or delete the rows with unique, non-duplicate values in the first column or, lacking that, put a 0 or 1 in a helper column.

 

[Barry Katcher]

See the sample below. It uses a helper column (col. B). The formula in B1, copied down, is:
=IF(COUNTIF($A$1:$A$100,A1)>1,"dupe","").

You can then filter on column B for "dupe" and delete those rows, or copy>paste them somewheres else for analysis.

Book1
	A	B	C	D
1	Barry	dupe
2	Elf	dupe
3	Geri	dupe
4	Stephen
5	Barry	dupe
6	Elf	dupe
7	Geri	dupe
8	George
Sheet1

 

[gideonfell]

I'll try it. Thanks.