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How to modify the values of the parameters passing via ...

Rui Barradas 
Hello,

You could see what is fun1 receiving with this modification meant for 
debugging:

fun1 <-function(x, y, z=10){
     print(match.call())
     x + y + z
}

Anyway, there is s standard way of dealing with argument '...' when one 
needs to know what was passed.
Include dots <- list(...) at the beginning of fun2 and then use it when 
necessary:

fun1 <-function(x, y, z=10){x + y + z}

fun2 <-function(aa, ...) {
   dots <- list(...)
   a <- fun1(x=aa, y=5)    # works well  a=1+5+10=16
   b <- fun1(x=aa, ...)    # works well  b=1+4+8=13
   y <- 0                  # it will not affect values passed using ...
   c <- fun1(x=aa, ...)    # works well but c = 1+4+8=13
   d <- fun1(x=aa, y=5, dots$z)  # works well  d=1+5+8=14
   c(a, b, c, d)
}

fun2(aa=1, y=4, z=8)
[1] 16 13 13 14


Also, to end statements with ';' is a C language tique, R doesn't need it.
(Nor it hurts.)

Hope this helps,

Rui Barradas

Em 30-08-2012 23:07, Zhiqiu Hu escreveu:

Thread (3 messages)

Zhiqiu Hu How to modify the values of the parameters passing via ... Aug 30 Rui Barradas How to modify the values of the parameters passing via ... Aug 30 Bert Gunter How to modify the values of the parameters passing via ... Aug 31