This is a guess since you didn't say where it comes from. It looks like a data.frame where some rows were deleted. Also, note that the column names in your example are sorted alphabetically instead of numerically. This example shows one way to get that behavior.
Rich > tmp <- data.frame(matrix(1:24, 6, 4, dimnames=list(1:6, c(1,2,11,12)))) > tmp X1 X2 X11 X12 1 1 7 13 19 2 2 8 14 20 3 3 9 15 21 4 4 10 16 22 5 5 11 17 23 6 6 12 18 24 > dimnames(tmp)[[2]] <- sort(dimnames(tmp)[[2]]) > tmp X1 X11 X12 X2 1 1 7 13 19 2 2 8 14 20 3 3 9 15 21 4 4 10 16 22 5 5 11 17 23 6 6 12 18 24 > tmp[c(2,5,3),] X1 X11 X12 X2 2 2 8 14 20 5 5 11 17 23 3 3 9 15 21 > On Wed, Jun 2, 2010 at 5:47 PM, Changbin Du <changb...@gmail.com> wrote: > > dim(tmp) > [1] 576 12 > > tmp > > 1 10 11 12 13 2 3 4 5 6 7 9 > 1 0 0 0 0 0 0 0 12 0 0 0 0 > 2 0 0 0 0 0 0 0 15 0 0 0 0 > [[alternative HTML version deleted]] ______________________________________________ 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.