On Aug 3, 2011, at 12:30 , Jannis wrote: > Dear List, > > > > i would like to mimic the behaviour or the following indexing with a do.call > construct to be able to supply the arguments to `[` as a list: > > > test = matrix[1:4,2] > > result = test[2,] > > > My try, however, did not work: > > result = do.call(`[`,list(test,2,NULL)) > result = do.call(`[`,list(test,2,)) > result = do.call(`[`,list(test,2,'')) > > > How can I use the do.call in that way with leaving the second indexing vector > blanc? >
alist() actually allows this, although probably more by coincidence than by design. Watch: > do.call(`[`, alist(test, 2, )) [1] 2 4 If you want to turn this into a programming idiom, be aware that there are subtle differences because alist() does not evaluate its arguments. E.g., the two plots below are not quite the same. > x <- 1:10 > y <- rnorm(10) > do.call(plot, list(x, y)) > do.call(plot, alist(x, y)) -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd....@cbs.dk Priv: pda...@gmail.com "Døden skal tape!" --- Nordahl Grieg ______________________________________________ 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.
