Dear Baptiste,
I know I have seen this discussed before but I haven't been successful
in searching for ellipsis, dots, ... in the archives. I would
like to filter ... arguments according to their name, and dispatch
them to two sub-functions, say fun1 and fun2. I looked at lm() but it
seemed more complicated than I need as it modifies the calling
function among other things. What is the best approach for this? My
current version presented below seems very awkward.
Best regards,
baptiste
sessionInfo()
R version 2.9.2 (2009-08-24)
i386-apple-darwin8.11.1
fun1 - function(col, row){
print(col)
print(row)
}
fun2 - function(x){
print(x)
}
foo - function(..., lty=1){
dots - list(...)
cl - match.call()
col - eval.parent(cl$col)
row - eval.parent(cl$row)
params.fun1 - c(col, row)
removed - na.omit(match(names(cl), params.fun1))
# index whichever arguments were passed to fun1
fun1(col, row)
fun2(dots[seq_along(dots)[-removed]])
Instead of passing all remaining arguments stacked into
one list (= 1 argument x to function fun2) you might want
to be able to retain them as distinct arguments;
so you might want to replace fun2 by
fun2.a - function(...) print(list(...))
and the call to fun2 in foo by
do.call(fun2.a, dots.remaining)
where, sticking to your code, you could obtain
dots.remaining as
removed - na.omit(match(names(cl), params.fun1))
dots.remaining - dots[seq_along(dots)[-removed]]
or by
removed - c(lty,params.fun1)
## I assume you do not want to pass on argument lty...
dots.remaining - cl[-1] ### remove the function name
dots.remaining - dots.remaining[! names(dots.remaining)
%in% removed]
Best, Peter
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