On 11-08-16 6:28 AM, Carl Witthoft wrote:
Sorry - I wanted to dig a bit deeper than that. I certainly appreciate your point, as well as the other recent responses, but what I'm trying to figure out is: what does the last function called do to interpret the "..." ? Suppose I have:
The best source for this (but it's not easy) is to look at the R sources. "..." is called R_DotsSymbol there. Most of the important handling happens in https://svn.r-project.org/R/trunk/src/main/eval.c, but it also shows up in a number of other places.
Duncan Murdoch
foo<-function(x,y,...){ z<-x+y plot(z,...) } I am fully comfortable with that sort of use. But, what does plot (or its internal calls) use for code to turn the contents of "..." into local named arguments? Is it something like arg.dot<-list(...) if ( some_match_func("foo", names(arg.dot) ) foo<-arg.dot$foo else foo<- default_value ? Or are there better constructs? thanks again for all info, and for your patience with me :-) Carl On 8/15/11 9:40 PM, Comcast wrote:Inside your function that has a ... argument, you can get the optional arguments with : Arg.dot<- list(...) Section 2.1.5 of the R Language Definition which should be accessible from the help facility would appear to be sensible place to start. "Programming for Data Analysis" could also be purchased.
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