Duplicates in Numbers

If you want to see if there are any duplicates in one column of email addresses, here is one simple method;

Formula in all cells of column B =COUNTIF(A,A)

It tells you how many times that row's email address appears in the table. It is not the easiest for deleting the duplicates, though, you cannot simply delete all that have 2's or 3's next to them or you'll end up removing those addresses completely. You could sort by columns B then A to get all the duplicates together to make it easier to pick through them.

Some other commonly used formulas for locating duplicates are a little broken right now, assuming you would like to sort the duplicates all into one block for a quick one-and-done deletion. Apple introduced a bug into Numbers and has not fixed it yet to the best of my knowledge.

If you're just looking for duplicates in the email column then a quick way to spot duplicates is to use the built-in Categories function.

Select the column with the emails and choose Organize > Add Category for "Name of Column."

In a second or so, without having entered formulas, you will quickly be able to see where there are duplicates.

If both the first column and the second column together have to be duplicated then just select the second column and Organize > Add Category for ... Again, you'll immediately be able to spot where there are duplicates.

SG

Another way to do it, but one that will likely break if you try to sort the table, is

Formula in cell B2 =IF(COUNTIF(A$2:A2,A2)>1, "Duplicate" , "")

Fill down to the bottom of the column.

Any that have the word "duplicate" can be selected and deleted. Don't sort the table, though.

If, on the other hand, you have two columns of emails and you're trying to spot which ones in the second list are in the first list then you could do something like this:

In C2, filled or copied down:

IFERROR(MATCH(B2,A,0)>0,"")

SG

I think you have to provide more detail, because on face value this is a simple problem to solve.

Given column A containing email addresses, and Column B also containing email addresses, I think you're trying to see if the value in column A matches the value in column B for any given row, right?

In which case this is a simple formula in Column C:

=IF (A2 = B2, "Duplicate", "")

This compares cells A2 and B2 and if they match outputs the value "Duplicate":

That appears to satisfy your request. If I'm missing something, please post back with more details (and maybe example data) so that I can advise further.

You have a column containing thousands of email addresses.

You have a second column in the same table containing unspecified content.

You want to determine if you have any duplicates.

Question: What determines that 'this is a duplicate'?

Is a duplicate email address enough to determine "This is a duplicate"?

Is a duplicated entry in the second column enough to determine that "this is a duplicate"?

How many "duplicates" are there in this four row list?

Can you list them?

Regards,

Barry

(not @b.com)