To prevent duplicate entries using Data validation.

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Hi,

I juz wanna prevent the duplicate entries in a range using the data validation. I know , we can use the "custom list" in data validation and use the formula =countif(range,criteria)=1 to prevent the duplicates. But My problem is typical..In the selected range, i will use the text "NA" and some numbers. So i juz want the numerics to be prevented in the data validation. If i use the above countif formul, it also prevents the word "NA". But i need "NA" to be allowed and to prevent only the numbers.

Can anyone help me out?-------------------------------------------------

See

http://www.excel-it.com/data_validation.htm

Hi,

How about this, presuming the validated range is all of column A, starting at A1

=OR(NOT(ISNUMBER(A1)),COUNTIF($A:$A,A1)=1)

EDIT:
or more simply

=OR(ISTEXT(A1),COUNTIF($A:$A,A1)=1)