How do I de-dupe two columns of data in excel?

[Anna 333]

I have two columns of extemely complex codes and I need to de-dupe them. I'm
not sure how to do this. Any help will be much appreciated.

Thanks

 

[Bernie Deitrick]

Anna,

If you have duplicates _within_ the lists, use a formula like

=COUNTIF(A:A,A2)

and then copy down to match your list. Any value > 1 shows a duplicated value.

If you are looking for the second, third, etc, instance of the duplicate, then use

=COUNTIF($A$1:A2,A2)

and copy down.

For values duplicated in the _other_ list, use something like

=NOT(ISERROR(MATCH(A2,D,False)))

which will return true if the value in cell A2 appears in column D. Again copy that formula down to
match your list.

HTH,
Bernie
MS Excel MVP

 

[ejschmitt2000]

To pull out of your lists only 1 record of each item, select the list then
used Data/Filter/Advanced Filter. This will bring up a dialogue box which
allows you to filter the list in place or copy to another location - but
whichever you choose be sure to select the check box for "Unique Records Only.

 

[Dave Peterson]

Does this mean that you want the "duplicateness" of the row based on two
columns?

If yes, then I'd add a couple of helper columns.

The first would concatenate the two key columns:

=a1&char(1)&b1
and drag down

Then I'd use that formula that Bernie suggested.

Or one of the techniques at Chip Pearson's site:
http://www.cpearson.com/excel/Duplicates.aspx