[R] accessing the attributes of a list inside lapply()

[Spencer Graves]

      Maybe I misunderstand your problem, but I wonder if you've 
considered "names": 

 > l <- list(a = 1, b = 3, c = 'asd')
 > names(l)
[1] "a" "b" "c"    

      hope this helps.  spencer graves
p.s.  I can't parse your "lapply(l, get_attr)".  In R 1.9.1 and R 2.0.0 
Patched, I get the following: 

 > lapply(l, get_attr)
Error in match.fun(FUN) : Object "get_attr" not found

Adrian Alexa wrote:

>Hello R-users, 
>
>
>I have the following problem, that I want to solve efficiently:
>
>
>I have a named list, for example:
>
>  
>
>>l <- list(a = 1, b = 3, c = 'asd')
>>l
>>    
>>
>$a
>[1] 1
>
>$b
>[1] 3
>
>$c
>[1] "asd"
>
>
>I know that I can iterate through it using lapply() function, but I
>would also like to able to get the list names or some attributes of l
>in the lapply(). For example if I use names() function in the call of
>lapply() I get:
>
>
>  
>
>>lapply(l, names)
>>    
>>
>$a
>NULL
>
>$b
>NULL
>
>$c
>NULL
> 
>
>My question is if I can get something like:
>
>
>  
>
>>lapply(l, get_attr)
>>    
>>
>$a
>[1] a
>
>$b
>[1] b
>
>$c
>[1] c
> 
>
>I can do this very easy with a for() loop but my list is quite big and
>I would like to get a decent running time. I don't need only the
>attributes of the list(I can obtain them by using attributes() or
>attr() function), but for my list the names of the elements are given
>me information that I need. Also I must mention that the elements of
>the list can by of any type.
>
>
>Any solution is welcome.
>
> 
>
>Many thanks, 
>
>Adrian 
>
>
>
>
>  
>

-- 
Spencer Graves, PhD, Senior Development Engineer
O:  (408)938-4420;  mobile:  (408)655-4567