Improvement....

I wrote:
=if(A1="","",if(A1,0,1))

=if(A1="", "", --NOT(A1))


----- original message -----

"JoeU2004" wrote in message
...
"LGriffin" wrote:
I am trying to reverse code 0s and 1s with =LOOKUP (reference cell,
{0,1},{1,0}). When the reference cell is empty, I'd like the function to
also return an empty cell.

=if(A1="","",if(A1,0,1))

treats all non-zero A1 as 1, changing them to 0.

A formula cannot "return an empty cell". It can only make a cell
__appear__ blank by returning a null string.

For that reason, use A1="", not ISBLANK(A1), to test for a blank cell.
ISBLANK() returns true only when the cell is truly empty -- that is, no
formula and no value. A1="" returns true in that case as well as when the
value in A1 is the null string, such as the result of IF() expression like
the above.