On Thu, Jan 2, 2014 at 7:16 PM, Henrik Bengtsson <h...@biostat.ucsf.edu> wrote: > Does it make sense to talk about the class of the output of > substitute(...)? I'm puzzled by the following outputs: > > ee <- list( > A = substitute( a <- 1 ), > B = substitute({ a <- 1 }), > C = substitute(( a <- 1 )), > D = substitute( a == 1 ) > ) > >> t(sapply(ee, FUN=function(e) { c(typeof=typeof(e), mode=mode(e), >> class=class(e)) })) > typeof mode class > A "language" "call" "<-" > B "language" "call" "{" > C "language" "(" "(" > D "language" "call" "call" > > That the mode in C is "(", is motivated in help("mode"): "that some > calls have mode "(" which is S compatible." However, what's the > explanation for the different classes? Is that intended or just > "garbage" output?
?class has: "Many R objects have a class attribute, a character vector giving the names of the classes from which the object inherits. If the object does not have a class attribute, it has an implicit class, "matrix", "array" or the result of mode(x) (except that integer vectors have implicit class "integer"). (Functions oldClass and oldClass<- get and set the attribute, which can also be done directly.)" which suggests either a bug or some tweaks are needed to the documentation. Is there any point in ever using mode() except for S+ compatibility? It just adds some confusing aliases on top of typeof. Hadley -- http://had.co.nz/ ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel