dumb question

[Guest]

I feel I should know the answer to this, but I don't, and I can't find it in
excel help.

What does "--" do in a formula?

I've seen it used in a few formulas (sumproduct & mmult specifically), and
I've even used it myself when advised to do so, but I don't quite understand
what it does. Can someone explain?

Thanks.

 

[Otto Moehrbach]

It's a shortcut way to convert a text number into a number value. HTH
Otto

 

[Bob Phillips]

See http://www.xldynamic.com/source/xld.SUMPRODUCT.html for a detailed
explanation.

--
HTH

Bob Phillips

(replace somewhere in email address with gmail if mailing direct)

 

[aidan.heritage]

-- is used when the function returns values of TRUE or FALSE, but you
need to do math on these results - it works like this

the first - forces Excel to convert the true and false to the numeric
equivalents - but of the OPPOSITE state (so true is now numeric 0 and
false is numeric 1). The second minus converts them BACK again - so 0
is now 1 and 1 is now 0 - this now means that in a function like
=sumproduct(--(a1:a10>10),--(b1:b10<90),c1:c10)

you will get results like
=1*1*ValueInC
if the first two conditions are true

or
=0*1*valueInC
if the first condition is false (extend this as you need to!!!)

 

[Dave Peterson]

-True becomes -1 (not 0)
--True becomes 1

-False becomes 0
--False stays 0

 

[aidan.heritage]

Yes, of course it does - I think my brain stopped working while my
fingers kept typing!

 

[Dave Peterson]

That's never happened to me, well, not in the last 10 minutes!