[Rd] standardization of slot access
Tony Plate
tplate at acm.org
Wed Sep 27 01:04:53 CEST 2006
I believe that the "accessor" functions you've read about are not the
slot() function, rather they are functions specifically designed for
extracting certain data from an object. An example is the 'coef()'
extractor function, which extracts coefficients from many model objects.
The name of the accessor function need not bear any resemblance to the
actual name of the slot in which the data is stored, and indeed, there
does not even need to be a one-to-one relationship between accessor
functions and slots.
AFAIK, slot() and '@' can be regarded as syntactic variants (please
correct me if I'm wrong).
-- Tony Plate
Sebastian P. Luque wrote:
> Hi,
>
> I'm usually confused about when to use 'slot' or '@'. I've frequently
> read that it's always preferable to use accessor functions, so I would
> think the '@' operator should be avoided. However, ?slot contains the
> following advise:
>
>
> "Generally, the only reason to use the functional form rather than the
> simpler operator is _because_ the slot name has to be computed."
>
>
> How do we decide whether to use the function or the operator?
>
>
> Cheers,
>
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