[R] Getting *types* of arguments?
Prof Brian Ripley
ripley at stats.ox.ac.uk
Thu Feb 17 13:34:26 CET 2005
On Thu, 17 Feb 2005, Georg Hoermann wrote:
> Hello world,
> short question: is there a possibility to get a list of
> arguments of a function *with* variable/parameter types?
Do you mean `argument' or `formal argument' or `parameter' or `variable'?
> formals() gives me the names of the parameters, but says
> nothing about the parameter type it expects (I know I can always use the
> help function).
> I would like somthing like
> $x: vector or data.frame...
No, because R's argument matching is polymorphic and many functions have
arguments that accept many types, or coerce arguments to the required
BTW, a data frame is a list which is a vector, so your example isn't very
realistic and shows that `type' is not a concept you have clear. R has
modes (?mode), types (?typeof) and classes (?class). Neither `vector' nor
`data frame' is a type.
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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