And to further the example, length() of matrix is not equal to the number of rows either.
> mm <- matrix(1:6, ncol=2) > length(mm) [1] 6 > dim(mm) [1] 3 2 Also, NROW() and nrow() are different; I'd be cautious about using NROW without making sure I understood the difference. > NROW function (x) if (is.array(x) || is.data.frame(x)) nrow(x) else length(x) <environment: namespace:base> > > > nrow function (x) dim(x)[1L] <environment: namespace:base> > -- Don MacQueen Lawrence Livermore National Laboratory 7000 East Ave., L-627 Livermore, CA 94550 925-423-1062 On 10/27/11 12:23 PM, "R. Michael Weylandt <michael.weyla...@gmail.com>" <michael.weyla...@gmail.com> wrote: >Data frame is list internally so length(df) = ncol(df) > >M > >On Oct 27, 2011, at 2:44 PM, Muhammad Abuizzah <izzah...@yahoo.com> wrote: > >> Hi, >> >> I am converting a data.frame to xts. the data.frame is 4 columns and >>1000 rows. I get a message that "NROW (x) must match length(order.by) >> class is data.frame, mode is list >> >> when I run >> dim(x) # I get >> 1000 4 #which is consistent with 1000 rows and 4 columns >> >> NROW (x) # I get >> >> 1000 # which is the right answer >> >> When I run length on each of columns in x separately using the "$" I >>get 1000, which is the right number too. >> So length on each of the columns individually gives me the right >>answer, but length on the data.frame gives me the number of columns >>instead of the number of rows, is there an explanation >> >> >> thanks >> >> ______________________________________________ >> 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. ______________________________________________ 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.
