Dear List:
In short, I am writing a number of functions as building blocks for
other functions and have some questions about scoping and passing arguments.
Suppose I have functions foo1, foo2, and foo3 such that:
foo1<-function(a=1,b=TRUE,c=FALSE){#do stuff};
foo2<-function(x=1,y=FALSE,z=c(1,2,3,4)){#do stuff};
foo3<-function(lambda,...){lambda*foo1()*foo2()};
I want to be able to pass a,b,c,x,y,z to the functions foo1 and foo2
though foo3 (whether I define default values or not). How do I do this?
I read a bit in the wiki about problems with partial argument matching
and argument matching (lesson: make argument names not match truncated
versions of other argument names in the "target" function).
To get a better feel for things I've been playing with examples such as:
b<-c(0.25,0.25);
fun<-function(a=1,...){a*b};
fun() returns 0.25 0.25 as expected.
fun(a=2) returns 0.5 0.5 as expected.
However, fun(b=1) returns 0.25 0.25 when I want to overwrite b with the
value 1 and have it return 1.
Likewise with
fun<-function(a=1,...){a*return(b)};
any argument I supply for b seems to be ignored.
I understand as b is not defined within the function when I enter
fun()
lexical scoping means R looks for b up one level and, finding b, uses it.
Thanks for any/all help.
Sincerely,
Jason Q. McClintic
--
Jason Q McClintic
UST MB 1945
2115 Summit Avenue
St. Paul, MN 55105
[EMAIL PROTECTED]
[EMAIL PROTECTED]
"It is insufficient to protect ourselves with laws, we must protect
ourselves with mathematics."--Bruce Schneier
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