Daniel Høyer Iversen wrote: > a=c(1,1,2); > is.matrix(a) gives FALSE > is.matrix(t(a)) gives TRUE > is.matrix(t(t(a))) gives TRUE > > Is this correct? Shouldn't all give FALSE? > I think is.matrix should give FALSE when dimension is 1*n or n*1.
No this is correct. is.matrix() returns TRUE if and only if the argument has a two-dimensional 'dim' attribute, and > dim(a) NULL > dim(t(a)) [1] 1 3 > dim(t(t(a))) [1] 3 1 (And is.array() depends on having a 'dim' attribute of positive length, so > dim(a) <- 3 > is.matrix(a) [1] FALSE > is.array(a) [1] TRUE ) -- O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
