From: Gabor Grothendieck <ggrothendieck_at_gmail.com>

Date: Tue 09 Jan 2007 - 15:38:35 GMT

R-help@stat.math.ethz.ch 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. Received on Wed Jan 10 02:56:59 2007

Date: Tue 09 Jan 2007 - 15:38:35 GMT

See below.

On 1/9/07, Farrel Buchinsky <fjbuch@gmail.com> wrote:

> You have assumed everything as I meant it.

*> I understand what is happening now. ls() simply creates a vector with
**> character elements and dim() sees each element as not having dimensions. The
**> critical part of what you have shown is the get(command) that turns what is
**> just a string into the dataframe or vector whose name is the string. The
**> other issue which you showed, and one that I have come across before is that
**> sapply and tapply and lapply cannot handle a function on a function. I would
**> have thought that I should get the same result from
**>
**> lapply(ls(),dim(get())) or something such as that.
*

The gsubfn package can do nearly that. Just preface the function of interest (in this case sapply) with fn$ and then you can write the function as a formula:

*> library(gsubfn)
**> fn$sapply(c("iris", "CO2"), ~ dim(get(x)), simplify = FALSE)
*

$iris

[1] 150 5

$CO2

[1] 84 5

*>
*

> But instead one has to create a function command within the lapply to handle

*> a dimension command upon a get command.
**>
**>
**> On 1/9/07, Barry Rowlingson <b.rowlingson@lancaster.ac.uk> wrote:
**> >
**> > Farrel Buchinsky wrote:
**> > > Why will the following command not work
**> > > sapply(objects(),dim)
**> > > What does it say about the objects list? What does it say about the dim
**> > > command?
**> > >
**> > > Likewise, the following also does not work
**> > > all<-ls()
**> > > for (f in all) print(dim(f))
**> >
**> > 'objects()' returns character strings - the names of objects - then
**> > the dim of the character strings are all NULL.
**> >
**> > I'll assume that's what you are getting at - you've not posted an
**> > example or the output you are getting or why it 'does not work'.
**> >
**> > Maybe you want this:
**> > > sapply(objects(),function(x){dim(get(x))})
**> > $f
**> > NULL
**> >
**> > $m
**> > [1] 2 5
**> >
**> > $x
**> > NULL
**> >
**> > $y
**> > [1] 5 2
**> >
**> > - where m and y are matrices, f is a function, x is a scalar.
**> >
**> > Barry
**> >
**> >
**>
**>
**> --
**> Farrel Buchinsky
**> Mobile: (412) 779-1073
**>
**> [[alternative HTML version deleted]]
**>
**> ______________________________________________
**> R-help@stat.math.ethz.ch 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.
**>
*

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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. Received on Wed Jan 10 02:56:59 2007

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