[R] Access comonents in lists of lists

[David Winsemius]

On Jan 11, 2013, at 3:26 PM, Bjoern Helm wrote:

> Hi,
> thank you. I just came up with
> 
> lapply(c(1:length(lst)), function(x) return(lst[[x]][[2]]))
> 
> 
> but your solution is much more elegant. Although I don't completely understand: if lst is the argument of function x[[2]] this should be iterpreted as lst[[2]]. Where am I wrong?

It would not be evaluated as lst[[2]] because 'lst' is not being passed. Only the individual values of lst are being passed. It returns lst[[1]][[2]], lst[[2]][[2]], lst[[3]][[2]], ..., lst[[length(lst]][[2]]

-- 
David.

> Björn
> 
> 
> Am 11.01.2013 15:44, schrieb arun kirshna [via R]:
>> Hi,
>> Try this:
>> lapply(lst,function(x) x[[2]])
>> #or
>> lst1<-lapply(lst,function(x) {names(x)<-1:3;x})
>> lapply(lst1,function(x) x$`2`)
>> #[[1]]
>> #[1] 1 2 3
>> 
>> #[[2]]
>> #[1] 4 5 6
>> 
>> A.K.
>> 
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> 
> 
> -- 
> Björn Helm
> Institut für Siedlungs- und Industriewasserwirtschaft
> Technische Universität Dresden
> D-01062 Dresden
> 
> Tel: +49 (0) 351 463 34616
> Fax: +49 (0) 351 463 37204
> 
> http://tu-dresden.de/hydro/siedlungswasserwirtschaft
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David Winsemius
Alameda, CA, USA