[R] binding rows from different matrices

[Peter Dalgaard]

Prof Brian Ripley <ripley at stats.ox.ac.uk> writes:

> You can almost always index in such problems: here is one way.
> 
> rbind(veca,vecb,vecc)[matrix(1:15, 3, byrow=T), ]
> 
> Take it apart of see how it works, if it is not immediately obvious.

Or, a little longer, but perhaps more intuitive:

 matrix(aperm(array(c(veca,vecb,vecc),c(5,5,3)),c(3,1,2)),15)

I.e., convert to array, do generalized transpose, convert back to
matrix. Not that I got the index calculations right on first try....

-- 
   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