From: Petr Pikal <petr.pikal_at_precheza.cz>

Date: Tue 16 Jan 2007 - 10:43:03 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 Tue Jan 16 22:13:45 2007

Date: Tue 16 Jan 2007 - 10:43:03 GMT

Hi

try different way of list definition, see below.

On 16 Jan 2007 at 10:10, Robin Hankin wrote:

From: Robin Hankin <r.hankin@noc.soton.ac.uk> Date sent: Tue, 16 Jan 2007 10:10:42 +0000 To: RHelp help <r-help@stat.math.ethz.ch> Subject: [R] "[[" gotcha

> The following gotcha caught me off-guard just now.

*>
**> I have two matrices, a and b:
**>
**>
**> a <- matrix(1,3,3)
**> b <- matrix(1,1,1)
**>
**> (note that both "a" and "b" are matrices).
**>
**> I want them in a list:
**>
*

B<-vector("list", 2)

B[[1]]<-a

B[[1]]<-b

here is no complain.

**HTH
**

Petr

> > B <- NULL

*> > B[[1]] <- a
**> > B[[2]] <- b
**> > B
**> [[1]]
**> [,1] [,2] [,3]
**> [1,] 1 1 1
**> [2,] 1 1 1
**> [3,] 1 1 1
**>
**> [[2]]
**> [,1]
**> [1,] 1
**>
**> >
**>
**> This is fine.
**>
**> But swapping "a" and "b" over does not behave as desired:
**>
**>
**> > B <- NULL
**> > B[[1]] <- b
**> > B[[2]] <- a
**> Error in B[[2]] <- a : more elements supplied than there are to
**> replace
**> >
**>
**>
**>
**> The error is given because after B[[1]] <- a, the variable B is
**> just a scalar and not a matrix (why is this?)
**>
**> What's the bulletproof method for assigning matrices to a list (whose
**> length is not known at runtime)?
**>
**>
**>
**>
**>
**>
**>
**>
**> --
**> Robin Hankin
**> Uncertainty Analyst
**> National Oceanography Centre, Southampton
**> European Way, Southampton SO14 3ZH, UK
**> tel 023-8059-7743
**>
**> ______________________________________________
**> 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.
*

Petr Pikal

petr.pikal@precheza.cz

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 Tue Jan 16 22:13:45 2007

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