How to detect uniques and count the number of cells with duplicate data

I know your example shows banana as unique, and you may be asking for the first instance of a row to display that way, but if not.....

=IF(COUNTIF($A$1:$A$7,A1)=1,"Unique",COUNTIF($A$1:$A$7,A1))

apologies if you truly intend the first row of an item to show as unique

I know this is an old question, but I see that it was never satisfactorily answered, so I hope this is still useful.

You want this:

=if(COUNTIF($A$1:$A1,A1)=1, "UNIQUE", COUNTIF($A$1:$A$7,A1))

This will fill down and look like this in subsequent rows:

=if(COUNTIF($A$1:$A2,A2)=1, "UNIQUE", COUNTIF($A$1:$A$7,A2))
=if(COUNTIF($A$1:$A3,A3)=1, "UNIQUE", COUNTIF($A$1:$A$7,A3))
...

And these are the results (assuming the formula was inserted into B1 and filled down):

    A         B
1 Apple     UNIQUE
2 Banana    UNIQUE
3 Banana    3
4 Banana    3
5 Cherry    UNIQUE
6 Date      UNIQUE
7 Date      2

The key to your problem is that you're looking for the first occurrence of the string to count as unique, then you count the duplicates. So, for the first part of the formula, you're really only searching the list so far, not the entire list.

This method also has the added advantage of working with an unsorted list as well as a sorted one.