Super Phil!! Thank you very much!! Mariana
On Sat, Feb 5, 2011 at 8:54 PM, Phil Spector <spec...@stat.berkeley.edu> wrote: > If the seq(5,205) was a typo, and should have been > seq(5,20,5), then what you're looking for is the outer > product of x and y: > >> x = seq(5,20,5) >> y = seq(5,20,5) >> x %o% y > > [,1] [,2] [,3] [,4] > [1,] 25 50 75 100 > [2,] 50 100 150 200 > [3,] 75 150 225 300 > [4,] 100 200 300 400 >> >> outer(x,y) > > [,1] [,2] [,3] [,4] > [1,] 25 50 75 100 > [2,] 50 100 150 200 > [3,] 75 150 225 300 > [4,] 100 200 300 400 > > The outer() function will accepts a FUN= argument which defaults to '*'. > > - Phil Spector > Statistical Computing Facility > Department of Statistics > UC Berkeley > spec...@stat.berkeley.edu > > > On Sat, 5 Feb 2011, Mariana Martinez-Morales wrote: > >> Hi guys: >> >> Sorry if this question is very basic. I’m learning basic matrix and >> vectors multiplication to develop a population matrix model for >> plants. I’m trying to multiply the elements of two vectors (each of >> the “x” values by each of the “y” values) to obtain a square matrix of >> xy values. >> >> f.e. >> x<-seq(5,205) >> y<-seq(5,20,5) >> stages<-c(“Sdl”, “Juv”, “Ad1”, “Ad2”) >> >> If I just multiply xy as a matrix >> xy<-matrix(x,y,nrow=4,ncol=4,dimnames=list(stages,stages)) >> >> I obtain this >> >> xy >> Sdl Juv A1 A2 >> Sdl 5 10 15 20 >> Juv 5 10 15 20 >> A1 5 10 15 20 >> A2 5 10 15 20 >> >> but what I want to obtain is this matrix >> >> Sdl Juv A1 A2 >> Sdl 25 50 75 100 >> Juv 50 100 150 200 >> A1 75 50 225 300 >> A2 100 200 300 400 >> >> ______________________________________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
