D dcstoo Jul 16, 2009 #1 What does the syntax in the subject denote? What is the purpose of "--" (double dash)?
D Dave Peterson Jul 16, 2009 #2 An expression like: a1:a4=1 will result in an array of 4 true/false elements. so the -- stuff in this expression --(a1:a4=1) will coerce the trues to 1's and the false's to 0's. -true = -1 --true = +1 This syntax is commonly used in array/sumproduct formulas. Adjust the ranges to match--but you can't use whole columns (except in xl2007). =sumproduct() likes to work with numbers. The -- stuff changes trues and falses to 1's and 0's. Bob Phillips explains =sumproduct() in much more detail here: http://www.xldynamic.com/source/xld.SUMPRODUCT.html And J.E. McGimpsey has some notes at: http://mcgimpsey.com/excel/formulae/doubleneg.html
An expression like: a1:a4=1 will result in an array of 4 true/false elements. so the -- stuff in this expression --(a1:a4=1) will coerce the trues to 1's and the false's to 0's. -true = -1 --true = +1 This syntax is commonly used in array/sumproduct formulas. Adjust the ranges to match--but you can't use whole columns (except in xl2007). =sumproduct() likes to work with numbers. The -- stuff changes trues and falses to 1's and 0's. Bob Phillips explains =sumproduct() in much more detail here: http://www.xldynamic.com/source/xld.SUMPRODUCT.html And J.E. McGimpsey has some notes at: http://mcgimpsey.com/excel/formulae/doubleneg.html
