I have been playing with true blanks, zeros, null strings etc.
and I have found subtle difference between COUNTBLANK
and ISBLANK......It can be confusing.

Eh, you'll get the hang of it! Let me add to your confusion!

In A1 enter =""
In B1 enter: =ISBLANK(A1)

How's that for confusion? MS should have named that function ISEMPTY.

Biff

"Epinn" wrote in message
...
Biff,

I will digest your most recent formula (with a twist) later on and I am sure
I'll learn something. Right now, I want to say this.

I am very glad that you have thought of blanks and changed the formula from
SUMPRODUCT/COUNTIF to COUNTA/FREQUENCY. In the last couple of days, I have
been playing with true blanks, zeros, null strings etc. and I have found
subtle difference between COUNTBLANK and ISBLANK, difference between COUNTIF
with "" as criterion and A1 (a blank cell never touched) as criterion etc.
etc. It can be confusing.

I included your SUMPRODUCT/COUNTIF formula as part of my experiment and I am
not sure if there is a bug with MS evaluate formula in terms of null
strings. The details can be found under the following thread in a post with
a date/time-stamp of 10/20/26 4:20 p.m.

http://tinyurl.com/yavg5y

I am including the link here in case anyone is interested. I know you are
probably busy.

I find something interesting in the following formula.

=IF(COUNTA(A1:A10),MAX(FREQUENCY(A1:A10,A1:A10))1 ,"")

COUNTA will count null strings ("") but not true blanks ("=") whereas
FREQUENCY ignores both null strings and true blanks. There shouldn't be any
conflict in the above formula, but I should keep in mind the difference for
future reference.

Just want to share with you what I have learned. Thank you for reading.

Hope the original poster don't mind me dropping by.

Epinn

"Biff" wrote in message
...
Dang!

I'll get it right one of these times!!!!!

=IF(COUNTA(A1:A10),MAX(FREQUENCY(A1:A10,A1:A10))1 ,"")

TRUE means there are dupes
FALSE means there are no dupes

Biff

"Biff" wrote in message
...
This is more robust:

=IF(COUNTA(A1:A10),MAX(FREQUENCY(A1:A10,A1:A10))=1 ,"")

With the first formula I was assuming ALL the cells in the range would
ALWAYS have something in them.

Biff

"Biff" wrote in message
...
Try this:

=SUMPRODUCT(COUNTIF(A1:A10,A1:A10))10

FALSE = no dupes
TRUE = dupes

Biff

"Tetsuya Oguma" wrote in message
...
Hi all,

I have a range, say, A1:A10, and want to check if any duplicate entry
exists
within this range.

What is the formula that returns True/False to do that?

Simple enough?

Tetsuya Oguma