[R] assignment in lists

[Prof Brian Ripley]

Philippe,

as.list(NULL) is the same as list(), and that is what I think you should
be using in both cases.  However, I do think that either both or neither
of your examples should work: my preference would be `neither' but as S
allows both it should be `either'.

Brian

On Thu, 26 Jun 2003, Philippe Grosjean wrote:

> Ok, I got it. I should have to define a as a list, in order to get a sane
> behaviour... That makes sense:
> 
> > a <- as.list(NULL)
> > a[["item"]] <- 1:3
> > a$item
> [1] 1 2 3
> 
> Best,
> 
> Philippe Grosjean
> 
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch]On Behalf Of Philippe Grosjean
> Sent: jeudi 26 juin 2003 5:25
> To: r-help at stat.math.ethz.ch
> Subject: [R] assignment in lists
> 
> 
> Hello,
> 
> I do not understand the following behaviour. Could someone explain me what
> happens?
> 
> > a <- NULL
> > a$item <- 1:3
> > a$item
> [1] 1 2 3
> > rm(a)
> > a <- NULL
> > a[["item"]] <- 1:3
> Error: more elements supplied than there are to replace
> 
> Why do I get an error message using list[["item"]], and not using list$item?
> Best,
> 
> Philippe Grosjean
> 
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-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595