What are "sep columns"?


You could use conditional formatting  for this. For this
example, I'll use some sample data  filling 4 rows. Open a new
sheet. Add the following conditional formats to cell A1 and C1.
(Select the "Formula Is" option and paste these formulas.) Set the
format to your normal background. Set the background for A1:D4 to
be highlighted.

A1 => = MATCH( $A1, $C$1:$C$4, 0 ) > 0
C1 => = MATCH( $C1, $A$1:$A$4, 0 ) > 0

Select cell A1 and use the + cursor to drag the cell to B1. Do
the same for cells C1 and D1. Now, select A1:D1 and use the +
cursor to fill 4 rows. Copy and paste these values only into range
A1:D4.

foo foo bar foo
bar foo bar foo
qaz bar car bar
qar bar foo bar

The matched email  addresses will be normal while the unmatched
cells will be highlighted.


: i have tried using loops  and formatting but it doesnt seem to
: work. is it because it is txt  as opposed to numbers?

Without seeing your code, it is pretty much impossible to tell
what may be wrong with it.