[R] Parsing for list components

Setzer.Woodrow@epamail.epa.gov Setzer.Woodrow at epamail.epa.gov
Thu Oct 18 18:45:26 CEST 2001


You just have to look a little deeper:

> parse(text="mylist$mycomponent")[[1]]
mylist$mycomponent
> parse(text="mylist$mycomponent")[[1]][[1]]
$
> parse(text="mylist$mycomponent")[[1]][[2]]
mylist
> parse(text="mylist$mycomponent")[[1]][[3]]
mycomponent

R. Woodrow Setzer, Jr.                                            Phone:
(919) 541-0128
Experimental Toxicology Division                       Fax:  (919)
541-5394
Pharmacokinetics Branch
NHEERL MD-74; US EPA; RTP, NC 27711


                                                                                                          
                    "G. Sawitzki"                                                                         
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                    10/18/01 11:35 AM                                                                     
                                                                                                          
                                                                                                          




How do I parse an identifier of a list component, e.g.
           mylist$mycomponent
or
           mylist[[1]] ?
Parse does not do the job, e.g.
           parse(text="mylist$mycomponent")
returns an expression with just one term, instead of "mylist", "$",
"mycomponent".

What I need is a way to extract the list name (e.g. "mylist"), given
an identifier of a component. Splitting the string is possible, but I
think there are better solutions.

   gs.

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