Changing Font Color meeting an argument

[John T. Kelly]

I have a column with numbers, these numbers are unique,
is there a way to write into a formula that if a number
repetes the color of the numbers turn red.

 

[Lance]

You could use comditional formatting. Select your range.
I will assume a1:a6 for the example. Under format
conditional formatting, choose "formula is" and write:

=COUNTIF($A$1:$A$6,A1)>1

set your pattern or font to color your dupes
Lance

 

[Bob Phillips]

.... and

if you only want to highlight previous instances of the repeat, that is not
the final repeat, use
=COUNTIF(A1:$A$6,A1)>1
or ignore the first instance, use
=COUNTIF($A$1:A1,A1)>1