simple matrix question
Paul Lemmens <P.Lemmens at nici.kun.nl> writes:
Hoi Christoph, --On woensdag 4 juni 2003 15:21 +0200 Christoph Lehmann <lehmann at puk.unibe.ch> wrote:
what is the easiest way to get from
x
x1 x2
[1,] 2 3
[2,] 3 2
[3,] 1 3
[4,] 1 4
xbar1
x1 x2
[1,] 1.75 3
[2,] 1.75 3
[3,] 1.75 3
[4,] 1.75 3
with the mean of the columns of x as values?
xbar1 <- tapply(as.vector(x), gl(2,4), mean);
No. I think you're missing the point (it gives a 2-vector rather than a 4x2 matrix, and apply(x,2,mean) is quicker for that). Try sweep(x,2,apply(x,2,mean),function(x,y)y)
O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907