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extracting a R object from an R image

4 messages · Bogdan Tanasa, Bert Gunter, Jeff Newmiller +1 more

Bert Gunter
# 
You can't. You can only save and load whole .RData files. You can, of
course, save and load separate R objects in separate files. But note
in ?save.image:

"For saving single R objects, saveRDS() is mostly preferable to
save(), notably because of the functional nature of readRDS(), as
opposed to load(). "

You may wish to search on "data serialization" (e.g. on Wikipedia) or
similar to better understand the underlying ideas.

Bert Gunter

"The trouble with having an open mind is that people keep coming along
and sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )

Bert Gunter

"The trouble with having an open mind is that people keep coming along
and sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
On Fri, Nov 5, 2021 at 3:01 PM Bogdan Tanasa <tanasa at gmail.com> wrote:
Jeff Newmiller
# 
IMO you are being a bit too literal. It is absolutely possible to load the file into a dedicated environment and use the $ or [[]] extraction operator to access a specific object in that environment.

?load
?new.env

Or, you can attach the file, copy to a new variable, and detach. (see examples in ?load)
On November 5, 2021 3:26:49 PM PDT, Bert Gunter <bgunter.4567 at gmail.com> wrote:

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Martin Maechler
    

    

      
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> IMO you are being a bit too literal. It is absolutely possible to load the file into a dedicated environment and use the $ or [[]] extraction operator to access a specific object in that environment.
    > ?load
    > ?new.env

    > Or, you can attach the file, copy to a new variable, and detach. (see examples in ?load)

Exactly: In the eyes of most R experts, it is the only useful use of attach():

   attach(".RData") 
   ls.str(2) # -> get alevel-1 str(.) of the objects in your image

        
> On November 5, 2021 3:26:49 PM PDT, Bert Gunter <bgunter.4567 at gmail.com> wrote:

        
>> You can't. You can only save and load whole .RData files. You can, of
    >> course, save and load separate R objects in separate files. But note
    >> in ?save.image:
    >> 
    >> "For saving single R objects, saveRDS() is mostly preferable to
    >> save(), notably because of the functional nature of readRDS(), as
    >> opposed to load(). "
    >> 
    >> You may wish to search on "data serialization" (e.g. on Wikipedia) or
    >> similar to better understand the underlying ideas.
    >> 
    >> Bert Gunter
    >> 
    >> "The trouble with having an open mind is that people keep coming along
    >> and sticking things into it."
    >> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
    >> 
    >> Bert Gunter
    >> 
    >> "The trouble with having an open mind is that people keep coming along
    >> and sticking things into it."
    >> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
    >> 
    >>

        
>> On Fri, Nov 5, 2021 at 3:01 PM Bogdan Tanasa <tanasa at gmail.com> wrote:

        
>>> 
    >>> Dear all,
    >>> 
    >>> I saved my work in a Rimage that contains multiple objects ;
    >>> 
    >>> the objects were generated with Monocle3 :
    >>> 
    >>> https://cole-trapnell-lab.github.io/monocle3/docs/starting/
    >>> 
    >>> one object is called CDS.
    >>> 
    >>> How shall I extract this object CDS (that has a complex structure) from the
    >>> R image ?
    >>> 
    >>> thank you,
    >>> 
    >>> Bogdan
    >>> 
    >>> [[alternative HTML version deleted]]
    >>> 
    >>> ______________________________________________
    >>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
    >>> 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.
    >> 
    >> ______________________________________________
    >> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
    >> 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.

    > -- 
    > Sent from my phone. Please excuse my brevity.

    > ______________________________________________
    > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
    > 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.