apply problem
On Sun, 17 Mar 2002 ggrothendieck at yifan.net wrote:
apply(iris3,1,function(x)identical(x,iris3[1,]))
1 2 3 FALSE FALSE FALSE What's wrong here?
iris3 is not an array, so it it coerced to one via as.matrix
[...]
and that's not the same object as your iris3
Thanks. Is there a way to iterate over the rows of a data frame without writing a loop -- that was my original objective.
No. A row of a data frame is still a data frame and therefore arbitrarily complex. In any case, in R apply() does write a loop. There are lots of legacy myths about the efficiencies of loops vs *apply(), but the reality it depends on the exact version of your S engine (and perhaps on how much memory you have). Just for the record, lapply() is the way to iterate over columns of a data frame.
Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._