"Claus Busch" wrote:
Am Fri, 20 Sep 2013 10:48:28 -0700 (PDT) schrieb :
Consider the formulae
=SUMPRODUCT(--(A1:A10="Luke Skywalker"),--(B1:B10="West"),D1:D10)
What does -- mean in front of --(A1:A10="Luke Skywalker")
and --(B1:B10="West")
-- changes TRUE to 1 and FALSE to 0 so that SUMPRODUCT can
calculate the values.
But note that there is nothing sacrosanct about double-negative (--). Any
arithmetic operation will treat TRUE and FALSE as the numbers 1 and 0.
So, for example, s.b.bhor's formula could be written:
=SUMPRODUCT((A1:A10="Luke Skywalker")*(B1:B10="West"),D1:D10)
Many people do not realize that. So they add double-negative unnecessarily,
to wit:
=SUMPRODUCT(--(A1:A10="Luke Skywalker")*(B1:B10="West"),D1:D10)