why should "--" be used in SUMPRODUCT formula

**TRJJK73** · 05-25-2009, 07:41 AM

Hi,

I have not used this SUMPRODUCT function very much and now I am trying to learn this. But I could not understand why "--" should be used as in a formula

=SUMPRODUCT(--(A2:A6="Active"), --(B2:B6>=10),--(C2:C6))

Is it a compulsion.?.

Can someone explain me the advantages and disadvantages of "--".

Thank you.

**zbor** · 05-25-2009, 08:01 AM

you can use 1* or 0+ instead of -- and you'll get same result.

**NBVC** · 05-25-2009, 08:06 AM

Have a read through this article:

Sumproduct

**DonkeyOte** · 05-25-2009, 08:08 AM

It used to coerce Booleans (True/False) to their integer equivalents (1/0 respectively). As zbor has implied you can coerce Booleans using a variety of operators, the double unary method (--) is regarded the most efficient.

For more info. on Sumproduct I would suggest reading through Bob Phillips' (MS Excel MVP) white paper on the subject - see the SUMPRODUCT link in my signature.