On Mon, 28 Jan 2008, hadley wickham wrote:
> Maybe this function won't actually be the help I had hoped it would
> be. Unfortunately some functions (e.g. glm via glm.control) throw
> errors when ... contain arguments that don't match some (eventual)
> argument list.
>
> Or is this a bug in glm? It certainly seems that the documentation
> should mention that ... is passed to glm.control, which only takes
> three arguments. I realise that this doesn't come up very often
> during an interactive model fitting session, and it is easy to remedy
> when it does, but it makes writing robust functions hard when a
> function with ... does in fact have a fixed argument list.
I think the docmentation has conflated '...' for glm and '...' for
weights.
My recollection is that this was intentional: at least one core developer
used to dislike '...' as it allowed mistyped argument names to be ignored.
And he has a good point, IMO.
>
> Hadley
>
> On Jan 28, 2008 8:19 PM, hadley wickham <[EMAIL PROTECTED]> wrote:
>> Has anyone developed a version of do.call that is safe in the sense
>> that it silently drops parameters that do not appear in the formals of
>> the called function? This is useful when ... ends up being used in
>> multiple further functions. e.g.
>>
>> f <- function(a, b) {a + b}
>> do.call(f, list(a=1, b=2, c=3)) # Errors
>> safe.call(f, list(a=1, b=2, c=3)) # Returns 3
>>
>> If have quickly thrown together the following, but it doesn't support
>> position based calls, and I'd like to avoid reinventing the wheel.
>>
>> safe.call <- function(f, params, f.params = names(formals(f))) {
>> if ("..." %in% f.params) {
>> safe.params <- params
>> } else {
>> safe.params <- params[intersect(f.params, names(params))]
>> }
>> do.call(f, safe.params)
>> }
>>
>> I hope to use safe.call to prevent a wide class of potential bugs in ggplot2.
>>
>> Hadley
>>
>> --
>> http://had.co.nz/
>>
>
>
>
> --
> http://had.co.nz/
>
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>
--
Brian D. Ripley, [EMAIL PROTECTED]
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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