There we go, thank you!


> On Fri, Feb 4, 2011 at 11:42 AM, Jeff Ryan <jeff.a.ryan@gmail.com> wrote:
>
>> Patrick,
>>
>> Take a look at all.vars to start with  That will return the vars as
>> characters, from there you can use get to test/proceed.
>>
>> > all.vars(parse.tree)
>> [1] "x"
>>
>>
>> Best,
>> Jeff
>>
>> On Fri, Feb 4, 2011 at 1:37 PM, Patrick Leyshock <ngkbr8es@gmail.com>
>> wrote:
>> > Hello,
>> >
>> > I'm trying to access an object, given only its name as a symbol.  I
>> cannot
>> > figure out how to proceed.  Suppose I call substitute( ) on the
>> expression
>> > 'x + 2':
>> >
>> >> parse.tree <- substitute(x + 2);
>> >
>> > The constituents of parse.tree are of type symbol and numeric:
>> >
>> >> str(parse.tree[[1]])
>> > symbol +
>> >
>> >> str(parse.tree[[2]])
>> > symbol x
>> >
>> >> str(parse.tree[[3]])
>> > num 2
>> >
>> > Suppose that x is S4 object, and that I need to access a slot of that
>> > object.  How can I do so, using only 'parse.tree' (or parse.tree coerced
>> > into a list)?
>> >
>> > Thanks, Patrick
>> >
>> >        [[alternative HTML version deleted]]
>> >
>> > ______________________________________________
>> > R-devel@r-project.org mailing list
>> > https://stat.ethz.ch/mailman/listinfo/r-devel
>> >
>>
>>
>>
>> --
>> Jeffrey Ryan
>> jeffrey.ryan@lemnica.com
>>
>> www.lemnica.com
>>
>
>

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