[R] How to manipulate an abitrary dimensioned array.

[Berton Gunter]

Not sure what you're after, but the kth dimension of an array y can be
obtained as:
apply(y,k,c). Each column of the resulting matrix can then be dimensioned,
if you like, via dim(y)[-k] .

-- Bert Gunter
Genentech Non-Clinical Statistics
South San Francisco, CA
 
"The business of the statistician is to catalyze the scientific learning
process."  - George E. P. Box
 
 

> -----Original Message-----
> From: Mike Meyer [mailto:mikem at salter-point.com] 
> Sent: Thursday, October 27, 2005 3:43 PM
> To: Berton Gunter
> Cc: r-help at stat.math.ethz.ch
> Subject: Re: [R] How to manipulate an abitrary dimensioned array.
> 
> Thanks for the suggestion.
> Perhaps I can see how to use apply to get the ratio, but say 
> I also want 
> to return X[,,,,1] in a general way.  Maybe I am being dense 
> but I just 
> don't see it --- probably as a result of too much Perl/Python/Java 
> recently that is clouding my mind.
> 
> So can someone suggest a general function that will give me the last 
> layer of an arbitrary dimensioned array?
> 
> Berton Gunter wrote:
> > Why doesn't apply() already do what you want?
> > 
> > -- Bert Gunter
> > Genentech Non-Clinical Statistics
> > South San Francisco, CA
> >  
> > "The business of the statistician is to catalyze the 
> scientific learning
> > process."  - George E. P. Box
> >  
> >  
> > 
> > 
> >>-----Original Message-----
> >>From: r-help-bounces at stat.math.ethz.ch 
> >>[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Mike Meyer
> >>Sent: Thursday, October 27, 2005 2:50 PM
> >>To: r-help at stat.math.ethz.ch
> >>Subject: [R] How to manipulate an abitrary dimensioned array.
> >>
> >>If I have an n1 x n1 x 2 array X I can calculate, say,
> >>X[,,1]/X[,,2].
> >>
> >>If it is a 4 dimensional array then I want to be able to calculate
> >>X[,,,1]/X[,,,2], and similarly for higher dimensions.
> >>
> >>How can I write a function to do this in a general way 
> >>without having to 
> >>do a switch for each possible length(dim(X)).  So I want a 
> function g 
> >>that will take an arbitrary dimensioned array, X, and return 
> >>X[,,,1]/X[,,,2], etc.   I know how to do this by turning X into a 
> >>vector, then doing the division, then re-shaping as an array, 
> >>but that 
> >>doesn't seem very elegant.
> >>
> >>What I think I am missing is how to paste/substitute/eval a 
> bunch of 
> >>commas into an array selection.
> >>
> >>Thanks, --Mike
> >>
> >>--
> >>Mike Meyer,  Seattle WA
> >>
> >>______________________________________________
> >>R-help at 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
> >>
> > 
> > 
> > ______________________________________________
> > R-help at 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
> 
> -- 
> 
> Mike Meyer,  Seattle WA
> 
> 
>