What is the purpose/meaning of the double dash (--) in this formula?

Thanks

"Sloth" wrote:

=SUMPRODUCT(--(MONTH(P2:AB659)=1)

change the 1 to the month number you want to count (ie. Jan=1, Feb=2, Mar=3,
etc.)

"Matt7102" wrote:

I seek help to find a formula to do the following:
I have a range (P2:AB659) that is populated with dates entered 1/16/06
format and displayed as 6-Jan format. I need to count the number of cells
containing any date in January, any date in February, etc.

TIA, Matt