Duplicate formula

[Cindy78]

Hi,

I have a column of letters and numbers
eg: A1234, D8956, Z5236 etc
Is there a formula I can put in another column to make sure that i dont use the same code twice?
Thanks

 

[T. Valko]

Hi,

I have a column of letters and numbers
eg: A1234, D8956, Z5236 etc
Is there a formula I can put in another column to make sure that i dont use the same code twice?
Thanks

You can use Data Validation to do this.

Select a range of cells that you'll be entering this data in. Let's assume the range is A2:A20.

Select the entire range A2:A20
Goto Data>Data Validation
Allow: Custom
Formula: =COUNTIF(A$2:A$20,A2)<2
OK