Feng, Ken wrote: > Hi, > > How do I ensure that I always get a matrix back when I extract rows? > > The mickey-mouse example doesn't matter much, but if instead of 1:2 or > 1, I have a vector which may have 1 or more values, then I'm in trouble. > > Any way to make this consistently return a matrix? > Thx in advance. > > - Ken > > # > ------------------------------------------------------------------------ > ------------------------- > > >> x <- matrix( 1:10, nrow = 5 ) >> x >> > [,1] [,2] > [1,] 1 6 > [2,] 2 7 > [3,] 3 8 > [4,] 4 9 > [5,] 5 10 > >> class( x[1:2,] ) >> > [1] "matrix" # this is good > >> class( x[1,] ) >> > [1] "integer" # this is EVIL >
class(x[1,,drop=FALSE]) [1] "matrix" # this is good (should be the default, perhaps) vQ ______________________________________________ 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.
