[R] changing function argument
dieter.menne at menne-biomed.de
Fri Mar 13 10:11:26 CET 2009
Thomas Mang <thomas.mang <at> fiwi.at> writes:
> I wonder if the following is possible in R:
> Suppose a function takes an argument, and wants to modify this argument
> so that the change is visible _at the call side_. It would be what is
> for example known as pass-by-reference-to-non-const in C++.
> test <- function(x)
> x <- 10
> return (somethingElse) # I do NOT want having to return x
> number = 5
> stopifnot(number == 10)
> Is there some trick with scoping rules and maybe <<- to achieve this ?
Yes, it is possible. No, don't do it (coming from the c++ world, I understand
your temptation). Try to look for "assign" to see the attached flames.
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