This has been a personal issue with me for a while John, since I screwed up
royally, by revising some formulas from the "*" style to the unary.
<<"Not sure what you mean when you say "the unary returns a zero".">>
I've a datalist that keeps track of the volatile pricing of dyestuff.
The cost of production is in part dependant on the price of the dye at the
time of purchase, then equated to the date of it's use on various lots of
fabric.
The datalist is populated by either importing the prices from the vendors
web site, or being keyed in by the office, from faxes or snail mail.
Need I say more !
Mixed data values !
BUT ... that *DIDN'T* matter with this formula:
=SUMPRODUCT((A2:A200<=D1)*(B2:B200=F15)*C2:C200)
A = dates
B = dyestuff name
C = prices
BUT definitely *DID* matter with this formula:
=SUMPRODUCT(--(A2:A200<=D1),--(B2:B200=F15),C2:C200)
Felt very proud that we were able to reduce costs to such a great extent.
That is, until the accounting department started reconciling inventories!
<<"Bottom line: it's the responsibility of the spreadsheet designer to
ensure that inputs are of the proper form.">>
Very true.
But just like 9/11 ... until it happens the first time, you don't really
give it much thought.
--
Regards,
RD
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Not sure what you mean when you say "the unary returns a zero".
First, if you're importing data, it's unlikely that you'll have a
structure like the one I suggested - it's far more likely that a table
of numeric values is intended to be imported as numbers, whether they
import as numbers or text. If D1

20 and E1:E20 contain imported data,
with all column D values imported as numbers, but all column E values
imported as Text,
=SUMPRODUCT(D1

20,E1:E20)
indeed returns zero, however
=SUMPRODUCT(--D1

20,--E1:E20)
returns the appropriate value.
Bottom line: it's the responsibility of the spreadsheet designer to
ensure that inputs are of the proper form. In a properly designed
application, you shouldn't have to worry about data type, or to cripple
valid functions to compensate for possible input errors.
And of course, in XL03 and XL04, at least, you get a smart button
popping up whenever you have "text numbers", offering to convert them...