What does -- mean?

[Ron]

I have been seeing "--" in formulae but cannot find an explanation of what
it is or does.

Example: =SUMPRODUCT(--(MONTH(B2:B13)=1), C2:C13)


--

Ron P

Sometimes you're the windshield
Sometimes you're the bug

 

[Bob Phillips]

See

http://www.xldynamic.com/source/xld.SUMPRODUCT.html
Multiple Condition Tests

for a full explanation.

--

HTH

RP
(remove nothere from the email address if mailing direct)

 

[Ken Wright]

As Peo pointed out in another post:-

For January you need to add another condition

=SUMPRODUCT(--(MONTH(A1:A100)=1),--(ISNUMBER(A1:A100)))

it's because that excel sees blank cells as zero and excel dates dtart with
January zero 1900 the unary minuses will convert boolean values of true and
false to 1 and 0

http://www.mcgimpsey.com/excel/formulae/doubleneg.html

 

[Ron]

See

http://www.xldynamic.com/source/xld.SUMPRODUCT.html
Multiple Condition Tests

for a full explanation.

--

HTH

RP
(remove nothere from the email address if mailing direct)

Thank you very much. It now makes sense.
Ron

 

[Ron]

As Peo pointed out in another post:-

For January you need to add another condition

=SUMPRODUCT(--(MONTH(A1:A100)=1),--(ISNUMBER(A1:A100)))

it's because that excel sees blank cells as zero and excel dates dtart
with
January zero 1900 the unary minuses will convert boolean values of true
and
false to 1 and 0

http://www.mcgimpsey.com/excel/formulae/doubleneg.html

Thank you very much. I hadn't come across this before. It makes sense.
Thanks

Ron