[R] stringification magic in subset?

[Sundar Dorai-Raj]

ivo welch said the following on 5/2/2007 8:13 AM:
> dear R wizards:
> 
> I am trying to replace subset() with my own version that first checks
> that each name in the select statement has a corresponding name in the
> data set.  preferably, it would have the same syntax and semantics as
> subset() otherwise.
> 
> alas, subset works in interesting ways:
> 
> subset(d, select=col1)
> 
> works just like
> 
> subset(d, select="col1")
> 
> somehow, subset manages to "stringify" its argument in such cases.  Is
> it possible to duplicate the subset method one-for-one?
> 
> a minor question---where do I find the source definition such as that
> of subset(), which is defined in
> 
>> subset
> function (x, ...)
> UseMethod("subset")
> <environment: namespace:base>
> 
> any help, as usual, appreciated.
> 
> regards,
> 
> /ivo
> 
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Try:

methods("subset")

which will point you to "subset.data.frame". The latter code will answer 
your questions.

HTH,

--sundar