Thomas Lumley <tlumley at u.washington.edu> writes:
On Fri, 6 Jan 2006, casella at stat.ufl.edu wrote:
hi - in version 2.1 the command
-2^2
gives -4 as the answer. (-2)^2 is evaluated correctly.
So is -2^2. The precedence of ^ is higher than that of unary minus. It may be surprising, but it *is* documented and has been in S for a long time.
Pretty much standard too, for languages that have an exponentiation operator. AFAICS Fortran, Perl, SAS all have ** at higher precedence than unary minus (or equal, but evaluate right to left). Stata seems like it might be the exception.
O__ ---- Peter Dalgaard ?ster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907