[Rd] number of parameters of a function.

[Prof Brian D Ripley]

On Tue, 25 Jul 2000, Duncan Temple Lang wrote:

> 
>  Is there a way to programmatically determine how many arguments a function
> accepts? In S, one can compute this as 
>           length(theFunction) - 1
> and determine the parameter names  as
>           names(theFunction)
> due to the representation of functions.

length(formals(theFunction))

Something similar works in S-PLUS 5.x:

length(functionArgs(theFunction))

as I guess Duncan knows.

-- 
Brian D. Ripley,                  ripley@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 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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