I haven't quite figured out how I can change the environment of a function.
I have a main function and want to use different auxillary functions, which I
supply as parameter (or names). What I want to do is something like this:
main.fun=function(aux.fun,dat){
x <- 1
fun.dat()
}
aux.fun.one=function(){
mean(dat)+x
}
aux.fun.one=function(){
median(dat)-x
}
I don't want to transfer the dat variable as a parameter as it can get
pretty large. The enclosing environment of both auxillary functions is the
Global environ, so they cannot see neither dat nor x as they exist inside the
scope of the main function. So how do I do this?
Thanks,
René
[[alternative HTML version deleted]]
What's wrong with explicitly passing the variables as arguments to the
function?
aux.fun.one <- function(dat, x){
median(dat) - x
}
Hadley
On Sat, Oct 4, 2008 at 11:50 AM, Ren? Holst <rho at aqua.dtu.dk>
wrote:> I haven't quite figured out how I can change the environment of a
function.
> I have a main function and want to use different auxillary functions, which
I supply as parameter (or names). What I want to do is something like this:
>
> main.fun=function(aux.fun,dat){
> x <- 1
> fun.dat()
> }
>
> aux.fun.one=function(){
> mean(dat)+x
> }
>
> aux.fun.one=function(){
> median(dat)-x
> }
>
> I don't want to transfer the dat variable as a parameter as it can get
pretty large. The enclosing environment of both auxillary functions is the
Global environ, so they cannot see neither dat nor x as they exist inside the
scope of the main function. So how do I do this?
>
> Thanks,
>
> Ren?
>
> [[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.
>
>
--
http://had.co.nz/
Rene, What you have below does not make much sense. You have not provided a definition for fun.dat() nor have you given an example with which to run any of your functions. The issue you raise about passing 'dat variable as a parameter as it can get pretty large' is not an issue. Observe: ------------------> x <- rnorm(1000000) > gc()used (Mb) gc trigger (Mb) max used (Mb) Ncells 136213 3.7 350000 9.4 350000 9.4 Vcells 1091921 8.4 1540913 11.8 1091931 8.4> mean(x)[1] -0.0004251693> gc()used (Mb) gc trigger (Mb) max used (Mb) Ncells 136405 3.7 350000 9.4 350000 9.4 Vcells 1091962 8.4 1697958 13.0 1092837 8.4> object.size(x)[1] 8000024> mean(2*x)[1] -0.0008503386> gc()used (Mb) gc trigger (Mb) max used (Mb) Ncells 136413 3.7 350000 9.4 350000 9.4 Vcells 1091962 8.4 2441693 18.7 2091968 16.0 ------------------- x occupies most of the Vcells in R's memory. And the 'max used' does not increase when mean(x) is called - in other words, no copy of x is performed. Only when another object is created ( '2*x' ) does 'max used' increase - almost doubling. So, as long as you are not modifying 'dat' (in which case a local copy is made) , I think there is nothing to worry about. HTH, Chuck On Sat, 4 Oct 2008, Ren? Holst wrote:> I haven't quite figured out how I can change the environment of a function. > I have a main function and want to use different auxillary functions, which I supply as parameter (or names). What I want to do is something like this: > > main.fun=function(aux.fun,dat){ > x <- 1 > fun.dat() > } > > aux.fun.one=function(){ > mean(dat)+x > } > > aux.fun.one=function(){ > median(dat)-x > } > > I don't want to transfer the dat variable as a parameter as it can get pretty large. The enclosing environment of both auxillary functions is the Global environ, so they cannot see neither dat nor x as they exist inside the scope of the main function. So how do I do this? > > Thanks, > > Ren? > > [[alternative HTML version deleted]] > >Charles C. Berry (858) 534-2098 Dept of Family/Preventive Medicine E mailto:cberry at tajo.ucsd.edu UC San Diego http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901
Please provide complete examples that include test drivers.
Here is main.fun reworked to eliminate the error in the arg
list and also changing the environment of aux.fun:
main.fun <- function(aux.fun, dat) {
x <- 1
environment(aux.fun) <- environment()
aux.fun()
}
aux.fun.one <- function() mean(dat) + x
aux.fun.two <- function() mean(dat) - x
main.fun(aux.fun.one, 1:10)
main.fun(aux.fun.two, 1:10)
This can also be done with the proto package:
P is a proto object used as a Trait in the sense of the proto vignette.
(A Trait plays the role of a class but its actually an object just like
all other proto objects and is not a separate construct.) P has the
fun method as its only component.
p1 and p2 are children of P. They each have dat and aux.fun
as components.
P delegates fun to each of p1 and p2 and when p1$fun() and p2$fun()
run they also create an x component in p1 and p2.
library(proto)
P <- proto(fun = function(this) { this$x <- 1; this$aux.fun()})
p1 <- P$proto(dat = 1:10, aux.fun = function(this) with(this, mean(dat) + x))
p1$fun()
p2 <- P$proto(dat = 1:10, aux.fun = function(this) with(this, mean(dat) - x))
p2$fun()
# look at p1 and p2
p1$as.list()
p2$as.list()
# If children p1 and p2 are never themselves parents then additional
simplification is
# possible.
p1 <- P$proto(dat = 1:10, aux.fun = function(this) mean(dat) + x)
p1$fun()
p2 <- P$proto(dat = 1:10, aux.fun = function(this) mean(dat) - x)
p2$fun()
On Sat, Oct 4, 2008 at 12:50 PM, Ren? Holst <rho at aqua.dtu.dk>
wrote:> I haven't quite figured out how I can change the environment of a
function.
> I have a main function and want to use different auxillary functions, which
I supply as parameter (or names). What I want to do is something like this:
>
> main.fun=function(aux.fun,dat){
> x <- 1
> fun.dat()
> }
>
> aux.fun.one=function(){
> mean(dat)+x
> }
>
> aux.fun.one=function(){
> median(dat)-x
> }
>
> I don't want to transfer the dat variable as a parameter as it can get
pretty large. The enclosing environment of both auxillary functions is the
Global environ, so they cannot see neither dat nor x as they exist inside the
scope of the main function. So how do I do this?
>
> Thanks,
>
> Ren?
>
> [[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.
>
>