What does — (minus minus) do in Excel? [duplicate]

Question

This question already has an answer here:

• Meaning of two minus signs together (“double unary”) 1 answer

In Excel I have two cells

A1 Gwen Stefani
B1 =SUMPRODUCT(--(A1:A10="Gwen Stefani"))

B1 records a value of 1 (it counts "Gwen Stefani" in cell A1)

My question is this: What is the -- operator called, for want of a better word, and what does it do?

• Naturally looking up "--" in Excel help gets me 50,200 results of - which isn't helpful ;)

Answer 1

The (A1:A10="Gwen Stefani") evaluates to an array (TRUE, FALSE, FALSE, FALSE...). So you are multiplying it by 1 to get (1,0,0,...). The "- -" can be replaced by "1*" with the same result.