how to change multiplier using letters

[april]

i saw this post sometime ago and cut it out for future use. yesterday i was
trying to test it out and the lookup solution doesn't work if B1 is blank.
it returns #NA. the other two cells work.

i know that one of the solutions had an if statement and that works but i am
curious why the lookup doesn't work.

thanks for your help.

 

[Luke M]

To help us out, could you post the formula you are referring to?

Without it, my best guess is that the minimum value in the LOOKUP table is
greater than *blank*, and thus the LOOKUP table can't find anything of equal
or lesser value in the table to match to the blank cell.

 

[april]

The discussion subject was RE: How to change multiplier using letters. it
was dated 10/27/2008. Joel gave this solution

=a1*lookup(b1,{"D","T","";1.5,8,2})

a1 = 8
b1 requires an input in letter form, such as "D" or "t" or it is left empty
if b1 = d then c1 = a1*1.5
if b1 = t then c1 = a1*8
if b1 is empty then c1 = a1*2

thanks

 

[Gary''s Student]

=A1*IF(ISNA(LOOKUP(B1,{"D","T","";1.5,8,2})),2,LOOKUP(B1,{"D","T","";1.5,8,2}))