Hi
Godmar Back <god...@gmail.com> napsal dne 09.07.2009 14:09:42:
> On Thu, Jul 9, 2009 at 4:50 AM, Petr PIKAL <petr.pi...@precheza.cz>
wrote:
> Hi
>
> r-help-boun...@r-project.org napsal dne 09.07.2009 02:57:33:
>
<snip>
> Not so weird. What do you expect from
>
> c(1:5, 10:20, 30:50)
>
> You mean what I expect personally, with my background?
> I'd expect a jagged array of arrays.
>
> 1 2 3 4 5
> 10 11 12 .. 20
> 30 31 .. 50
>
> If operator c() constructs an array out of its arguments, and if the
sequence
> operator : constructs an array, then c(1:5) should construct an array of
arrays.
> is.array(1:5)
[1] FALSE
> is.vector(1:5)
[1] TRUE
>
Why. Not much is said about arrays in man page for c. The operator
concatenates its arguments. If they are vectors the output is again a
vector. If they are lists the output is list.
try
c(1:5,10:20)
c(1:5, list(10:20)
c(1:5, data.frame(10:20)
and regarding arrays, matrices and vectors - AFAIK arrays and matrices are
just vectors with dim attribute, which is stripped by c
c is sometimes used for its side effect of removing attributes except
names, for example to turn an array into a vector. as.vector is a more
intuitive way to do this, but also drops names. Note too that methods
other than the default are not required to do this (and they will almost
certainly preserve a class attribute).
>
> That is basically what your function do. With slight modification you
can
> get tabular output without mapply
>
> multipleoutput <- function (x) {
> result.s <- x^2
> result.c <- x^3
> result.e <- exp(x)
> cbind(square=result.s, cube=result.c, exp=result.e)
> }
>
> Just for clarification: is there any significance to your using the . in
the
> names result.s, result.c, etc. like there would be in some other
languages
> where dot is an operator?
No. AFAIK one dot does not have any special meaning unless you use it in
the beginning of name. In that case the variable is not listed by ls()
function. See ?ls and argument all.names
Regards
Petr
>
> - Godmar
______________________________________________
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.
