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Scoping rules in R

3 messages · Brian Ripley, Nicholas Lewin-Koh

Nicholas Lewin-Koh
# 
Hi,
The following is a small test function that is part of a larger piece of
code. If I understand things correctly both z and st.obj$call need to be
looked for in .GlobalEnv . How do I write this so it works? And which part
of the documentation should I be reading to get a more in depth
explanation?

Thanks
Nicholas


tst<- function(st.obj,z){
G<-unique(st.obj$mem[,st.obj$depth])
Gr<-st.obj$mem[,st.obj$depth]

cphlst<-list()

for(i in G){
  assign("form",deparse(substitute(st.obj$cph.call)),env=.GlobalEnv)
  dat<-z[Gr==i,]
  call<-paste("coxph(",form ,",data= ",dat,")")
  cphlst[[j]]<-eval(parse(text=call), sys.parent())
  }
cphlst
}

                 CH3
                  |
                  N             Nicholas Lewin-Koh
                 / \            Dept of Statistics
           N----C   C==O        Program in Ecology and Evolutionary Biology
          ||   ||   |           Iowa State University
          ||   ||   |           Ames, IA 50011
          CH    C   N--CH3      http://www.public.iastate.edu/~nlewin
            \  / \ /            nlewin at iastate.edu
             N    C
             |   ||             Currently
            CH3   O             Graphics Lab
                                School of Computing
                                National University of Singapore
     The Real Part of Coffee    kohnicho at comp.nus.edu.sg


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Brian Ripley
# 
Could you tell us what you are trying to achieve here?  It looks to me as
if update() would do this sort of thing much more transparently.  Since
tst()  could be called from inside a function, you don't want to flout the
normal scope rules without a very good reason.
On Thu, 21 Mar 2002, Nicholas Lewin-Koh wrote:

            

      
      
      
    

        

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Nicholas Lewin-Koh
    

    

      
      #
    

  


  

      
Hi,
Thanks for the quick reply, 

In the function st.obj is a survival tree object (my own, not rpart). z is
the original data. The first part just gets a vector of node assignments
from the st.obj. The second part where the trouble is, is looping through
the terminal nodes fitting a coxmodel for each node on the data subset,
the correct formula for the node is retrieved from st.obj, and that and
subsetting z seem to be where the scoping problem is.

I hope this is clearer.

Thanks
Nicholas

        
On Thu, 21 Mar 2002 ripley at stats.ox.ac.uk wrote:

        

            

      
      
      
    

        
CH3
                  |
                  N             Nicholas Lewin-Koh
                 / \            Dept of Statistics
           N----C   C==O        Program in Ecology and Evolutionary Biology
          ||   ||   |           Iowa State University
          ||   ||   |           Ames, IA 50011
          CH    C   N--CH3      http://www.public.iastate.edu/~nlewin
            \  / \ /            nlewin at iastate.edu
             N    C
             |   ||             Currently
            CH3   O             Graphics Lab
                                School of Computing
                                National University of Singapore
     The Real Part of Coffee    kohnicho at comp.nus.edu.sg


-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-help-request at stat.math.ethz.ch
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