[R-sig-teaching] pros/cons of teaching attach()
Murray Jorgensen
maj at waikato.ac.nz
Sat Sep 25 01:45:17 CEST 2010
This may not always be useful when we venture too far from the cosy
world of lm().
For example I have just been looking at the function flexmixedruns()
from package fpc, and the object fr that is its value in the examples
for that function.
> methods(class=class(fr))
just produces the standard list methods because fr is defined as a list.
To get stuff out you need $.
Still I like Gabor's suggestion and I will use it when a function
returns an object of an unusual class.
Murray
On 25/09/2010 11:07 a.m., Gabor Grothendieck wrote:
>
>
> On Fri, Sep 24, 2010 at 6:25 PM, Murray Jorgensen <maj at waikato.ac.nz
> <mailto:maj at waikato.ac.nz>> wrote:
>
> When will I ever learn to proof-read my emails?!
> =============
> I think what Greg sayS here is the "official wisdom" and it leads to
> more future-proofED code as the structure of various objects can
> change in new versions of R.
>
>
> OTOH the structure of a kind of object can always be explored with
> str(), but it may not be easy to find out what extractor functions
> are available for the object.
>
> Try this using builtin data.frame, BOD, to find methods can be applied
> to fm:
>
> fm <- lm(demand ~ Time, BOD)
> methods(class = class(fm))
>
> --
> Statistics & Software Consulting
> GKX Group, GKX Associates Inc.
> tel: 1-877-GKX-GROUP
> email: ggrothendieck at gmail.com <http://gmail.com>
>
--
Dr Murray Jorgensen http://www.stats.waikato.ac.nz/Staff/maj.html
Department of Statistics, University of Waikato, Hamilton, New Zealand
Email: maj at waikato.ac.nz majorgensen at ihug.co.nz Fax 7 838 4155
Phone +64 7 838 4773 wk Home +64 7 825 0441 Mobile 021 0200 8350
More information about the R-sig-teaching
mailing list