In this formula: =SUMPRODUCT(--(A1:A10="Open"))

this section: (A1:A10="Open")
returns a series of TRUE/FALSE values
....which are not numeric to Excel.

When an arithmetic operator (+,-,*,/) is applied to
a TRUE/FALSE value, Excel converts TRUE to 1 and FALSE to 0.

The standard convention is to use
the Double-Minus (--) to convert the values.

It works this way:
TRUE=TRUE
-TRUE = -1
--TRUE = 1

FALSE = FALSE
-FALSE = 0
--FALSE = 0

You could also use 1*TRUE, but the Dbl-Minus indicates to
knowledgable users that you are forcing a conversion and not
trying to calculate something.

So, in the formula, the TRUE/FALSE values
are converted to 1's and 0's by the "--" and
SUMPRODUCT calculates the result.

Does that help?
--------------------------

Regards,

Ron
Microsoft MVP (Excel)
(XL2003, Win XP)


"Negda" wrote in message
...
In some example I saw the use of double dashes at the beginning:
=sumproduct( -- (....))

What does it mean? when I should use it and to avoid?