R help - Feb 2012 - save objects of own function to workspace

Dear R-helpers,

I created an own function which looks like this

s_elternmz <- function(Var="balt")
{
  Dg_a<-mz[,c("asbhh","apkz",Var)]
  colnames(Dg_a)[colnames(Dg_a)=="apkz"]<-"bpkzm"
 
colnames(Dg_a)[colnames(Dg_a)==Var]<-paste(Var,"_m",sep="")
  mz_int<-merge(mz,Dg_a,by=c("asbhh","bpkzm"),all.x=T)
  colnames(Dg_a)[colnames(Dg_a)=="bpkzm"]<-"bpkzv"

colnames(Dg_a)[colnames(Dg_a)==paste(Var,"_m",sep="")]<-paste(Var,"_v",sep="")
 
mz_int<-merge(mz_int,Dg_a,by=c("asbhh","bpkzv"),all.x=T)
  mz_int <-
mz_int[order(mz_int$asbhh,mz_int$apkz),c(colnames(mz),paste(Var,"_m",sep=""),paste(Var,"_v",sep=""))]
 }

My problem is that the objects are not saved in the workspace. Especially I
need the object which I created in the end - mz_int - because I want to do
calculations with it in R afterwards.

Thank you very much for your help in advance.

Marion

	[[alternative HTML version deleted]]

On Feb 14, 2012, at 9:20 AM, Marion Wenty wrote:
> Dear R-helpers,
>
> I created an own function which looks like this
>
> s_elternmz <- function(Var="balt")
>     {
>  Dg_a<-mz[,c("asbhh","apkz",Var)]
>  colnames(Dg_a)[colnames(Dg_a)=="apkz"]<-"bpkzm"
> 
colnames(Dg_a)[colnames(Dg_a)==Var]<-paste(Var,"_m",sep="")
> 
mz_int<-merge(mz,Dg_a,by=c("asbhh","bpkzm"),all.x=T)
>  colnames(Dg_a)[colnames(Dg_a)=="bpkzm"]<-"bpkzv"
>
>
colnames(Dg_a)[colnames(Dg_a)==paste(Var,"_m",sep="")]<-
> paste(Var,"_v",sep="")
Why take two steps to change that column name?
> 
mz_int<-merge(mz_int,Dg_a,by=c("asbhh","bpkzv"),all.x=T)
You just overwrote an object that you created earklier but have not  
done anything with in the meantime.
>  mz_int <-
> mz_int[order(mz_int$asbhh,mz_int$apkz),  
> c(colnames(mz),paste(Var,"_m",sep=""),
paste(Var,"_v",sep=""))]
> }
>
> My problem is that the objects are not saved in the workspace.  
> Especially I
> need the object which I created in the end - mz_int - because I want  
> to do
> calculations with it in R afterwards.
Then just assign it:

mz_result <- s_elternmz()

As you have noticed, assignment inside a function is not a durable  
event. The function returns the value of either its first encounter  
with return() or the value
of hte last assignment (but not the name to which that object was  
assigned.) Welcome to R's version of functional programming.
>
> Thank you very much for your help in advance.
>
> Marion
>
> 	[[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.
David Winsemius, MD
West Hartford, CT

It is possible to do what you ask using <<- instead of <-, but from the
perspective of using the function it will be much clearer if you add mz as an
argument to the function along with Var, and return mz_int at the end. (The
easiest way to return a variable is to type it alone on the last line if your
function.) Then you can assign the return value to some variable of your
choosing (including possibly one named mz_int in the calling environment) where
you call the function.
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Marion Wenty <marion.wenty at gmail.com> wrote:
>Dear R-helpers,
>
>I created an own function which looks like this
>
>s_elternmz <- function(Var="balt")
>{
>  Dg_a<-mz[,c("asbhh","apkz",Var)]
>  colnames(Dg_a)[colnames(Dg_a)=="apkz"]<-"bpkzm"
> 
colnames(Dg_a)[colnames(Dg_a)==Var]<-paste(Var,"_m",sep="")
> 
mz_int<-merge(mz,Dg_a,by=c("asbhh","bpkzm"),all.x=T)
>  colnames(Dg_a)[colnames(Dg_a)=="bpkzm"]<-"bpkzv"
>
>colnames(Dg_a)[colnames(Dg_a)==paste(Var,"_m",sep="")]<-paste(Var,"_v",sep="")
> 
mz_int<-merge(mz_int,Dg_a,by=c("asbhh","bpkzv"),all.x=T)
>  mz_int <-
>mz_int[order(mz_int$asbhh,mz_int$apkz),c(colnames(mz),paste(Var,"_m",sep=""),paste(Var,"_v",sep=""))]
> }
>
>My problem is that the objects are not saved in the workspace.
>Especially I
>need the object which I created in the end - mz_int - because I want to
>do
>calculations with it in R afterwards.
>
>Thank you very much for your help in advance.
>
>Marion
>
>	[[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.