[R] persp(), scatterplot3d(), "..." argument

[Uwe Ligges]

Jari Oksanen wrote:

> On Wed, 2004-10-27 at 10:04, Uwe Ligges wrote:
> 
>>Robin Hankin wrote:
>>
>>
>>>Hello list.
>>>
>>>I very often need 3d scatterplots, and use scatterplot3D quite a lot.
>>>I am trying to modify persp() to plot scatterplots, and make use of
>>>the theta and phi arguments that persp() offers.  I am having some
>>>difficulty passing the correct arguments to persp().
>>>
>>>Here is my function so far.  Much of it is copied from the persp() manpage.
>>>work as expected, but all extra arguments are passed to persp() _and_
>>>lines() and this gives warnings.
> 
> ---cut---
> 
>>>
>>>QUESTION:
>>>
>>>What is best practice to handle this sort of problem?  Should I ignore
>>>the warnings() that this approach gives?  I can suppress them with
>>>options(warn= -Inf), but is this a good idea?  I've read section 10.4
>>>of AITR.
>>
>>Many of us have thought about this problem.
>>I'd suggest to introduce frequently used arguments to your meta-function 
>>(such as main, xlab, ylab, ...), but ignore warnings (note: warnings, 
>>not errors) if less frequently arguments are passed through "...".
>>
>>Alternatively, you can exclude "..." from lines() or points() and 
>>specify a list of arguments to be passed to that call.
> 
> 
> This is a larger problem if 
> 1. one of the underlying functions does not have "..."
> 2. you want to relay arguments to two or more underlying functions, and
> 3. you don't want to list all possible arguments in your function
> definition, since it is long enough already.
> 
> The solution is still there, but it is (black) magic. For instance,
> 'arrows' does not have "...", so you must add them with this magical
> mystery string:
> 
> formals(arrows) <- c(formals(arrows), alist(... = ))


You don't need it for simple things like:

   foo <- function(...){
       plot(1:10)
       arrows(1,1,7,7,...)
   }

foo(lwd=5) # works!




> Yes, this is documented in R manuals -- I wouldn't know this otherwise.
> Still, it would be nicer if 'arrows' had "..."...

As always, useful patches are welcome.

Uwe Ligges


> 
> cheers, jari oksanen