Hi Chip, Try this:
# For Q1 R> C1 = rbind(A,B) or R> C2 = do.call(rbind,list(A,B)) R> all.equal(C1,C2) # TRUE # For Q2 R> set.seed(123) R> vx=1:10 R> A = matrix(rnorm(500),ncol=10) R> A2=t(sapply(A,rep,10)) R> A2[vx,]<- A[vx,] R> A2 R> dim(A2) # 500 10 R> dim(A) # 50 10 HTH, Jorge On Fri, May 9, 2008 at 2:28 PM, Chip Barnaby <[EMAIL PROTECTED]> wrote: > Greetings, > > Q #1 > ------ > > How does one combine data frames by row ... no cleverness a la merge(), > just add rows. > > For example, given A with 20 rows and B with 30 rows, I want C = combine( > A, B) having 50 rows. > > Columns having matching names should be filled from both (all) sources with > suitable coercion, unmatched would get NA in rows whose source does not have > that column. > > > Q #2 > ------ > > Given data frame A having various columns including "vx". > > I want to create a new data frame A2 that has 10 copies of each row in A, > all the same as the source row except vx=seq(1:10). The source row value of > vx is overwritten. A2 would have 10 times as many rows as A. > > I have of course discarded idea of using of a for loop, but maybe that is > what it takes. > > > TIA etc, > > Chip Barnaby > > > > > > > --------------------------------------------------------- > Chip Barnaby [EMAIL PROTECTED] > Vice President of Research > Wrightsoft Corp. 781-862-8719 x118 voice > 131 Hartwell Ave 781-861-2058 fax > Lexington, MA 02421 www.wrightsoft.com > > ______________________________________________ > 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. > [[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.
