[R] Using variables from different environments in one function
Ista Zahn
istazahn at gmail.com
Fri Oct 5 23:20:30 CEST 2012
Hi Rik,
I don't fully understand it, but setting local=TRUE to your source()
calls will avoid the specific error you noted.
Best,
Ista
On Fri, Oct 5, 2012 at 3:47 PM, Rik Verdonck
<Rik.Verdonck at bio.kuleuven.be> wrote:
> Dear R-community,
>
>
> I have been experiencing this issue with functions within a function and
> I can kind of feel where the problem is (environments, closures etc),
> but I don't manage to solve it.
>
> I will sketch it with an example:
>
> #We have two simple "inner" functions:
>
> ############## INNER FUNCTION1 #################
> innerfunction1<-function()
> {
> ab<-a+b
> cd<-c+d
> innerfunctionlist<-list("ab"=ab,"cd"=cd)
> }
> ################################################
>
> ############## INNER FUNCTION2 #################
> innerfunction2<-function()
> {
> print(AB+CD)
> }
> ################################################
>
> #And we have a main script with a number of predefined variables.
> #This shapes an environment in which variables that will be used
> #by the inner function are defined.
> ############# MAIN SCRIPT ################
> a=1
> b=2
> c=3
> d=4
>
>
> #source(filepath/to/innerfunction1)
> outcome1<-innerfunction1()
>
> AB <-outcome1$ab
> CD <-outcome1$cd
>
> #source(filepath/to/innerfunction2)
> innerfunction2()
>
>
> #################################################
>
>
>
> #So far so good. No problem if you run this.
> #The problem emerges if you want to make the main script a function.
> #So now I wrap it into a function:
>
>
> main<-function()
> {
> a=1
> b=2
> c=3
> d=4
>
> #source(filepath/to/innerfunction1)
> outcome1<-innerfunction1()
>
> AB <-outcome1$ab
> CD <-outcome1$cd
>
> #source(filepath/to/innerfunction2)
> innerfunction2()
> }
>
>
>
> when I now run main() in an environment where all these variables are not defined, I will get this error
> message:
>
> Error in innerfunction1() : object 'a' not found
>
> I can solve this by defining the variables a, b, c and d. However, I
> will then get next error message:
>
> Error in print(AB + CD) : object 'AB' not found
>
>
> I think I see what happens. The right variables are not present
> in the right environment. Probably I did something silly, but I really
> don't see how to solve this. Can someone please help me?
>
> Many thanks!
> Rik Verdonck
> University of Leuven
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
More information about the R-help
mailing list