[R] A way to list only variables or functions?
sdhyok at email.unc.edu
Mon Jun 21 17:23:28 CEST 2004
The ls.objects function displays a really nice summary about objects.
Surely, I will use it more often than ls or ls.str.
> -----Original Message-----
> From: Petr Pikal [mailto:petr.pikal at precheza.cz]
> Sent: Monday, June 21, 2004 AM 11:01
> To: Duncan Murdoch; r-help at stat.math.ethz.ch; sdhyok at email.unc.edu
> Subject: Re: [R] A way to list only variables or functions?
> On 21 Jun 2004 at 10:39, Duncan Murdoch wrote:
> > On Mon, 21 Jun 2004 09:53:35 -0400, "Shin, Daehyok"
> > <sdhyok at email.unc.edu> wrote :
> > >Glad to know useful functions.
> > >How about adding lsv.str function to list only variables bound to
> > >values? In my opinion, we are more interested in values than
> > >functions in the process of data analysis.
> > In R, functions often contain useful information about data (in their
> > attached environments). For example, the result of a smoothing fit
> > could include a function that calculates the fitted value at any
> > point. So the distinction between functions and values isn't as clear
> > as you seem to be thinking.
> > However, it would be useful to get a slightly more informative version
> > of ls(), that returned a data.frame containing the name, length,
> > class, and other useful information for each object. Then if you
> > didn't want to see functions, you'd just select based on the class (or
> > mode, or some other column).
> > I seem to recall that S-PLUS has such a function, but I forget the
> > name of it. Probably R does too, on CRAN if not in the base
> > packages.
> Some time ago there was a thread about such matter too and from
> that time i use a function
> > ls.objects
> function (pos = 1, pattern, order.by)
> napply <- function(names, fn) sapply(names, function(x)
> pos = pos)))
> names <- ls(pos = pos, pattern = pattern)
> obj.class <- napply(names, function(x) as.character(class(x)))
> obj.mode <- napply(names, mode)
> obj.type <- ifelse(is.na(obj.class), obj.mode, obj.class)
> obj.size <- napply(names, object.size)
> obj.dim <- t(napply(names, function(x)
> vec <- is.na(obj.dim)[, 1] & (obj.type != "function")
> obj.dim[vec, 1] <- napply(names, length)[vec]
> out <- data.frame(obj.type, obj.size, obj.dim)
> names(out) <- c("Type", "Size", "Rows", "Columns")
> if (!missing(order.by))
> out <- out[order(out[[order.by]]), ]
> which gives some more information about objects than plain ls()
> > Duncan Murdoch
> > ______________________________________________
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> Petr Pikal
> petr.pikal at precheza.cz
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