[R] Break during the recursion?

[Atte Tenkanen]

TNX Hadley!

Atte

----- Original Message -----
From: hadley wickham <h.wickham at gmail.com>
Date: Sunday, July 15, 2007 11:04 pm
Subject: Re: [R] Break during the recursion?

> On 7/15/07, Atte Tenkanen <attenka at utu.fi> wrote:
> > Here is now more elegant function for inorder tree walk, but I 
> still can't save the indexes!? This version now prints them ok, but 
> if I use return, I get only the first v[i].
> >
> > leftchild<-function(i){return(2*i)}
> >
> > rightchild<-function(i){return(2*i+1)}
> >
> > iotw<-function(v,i)
> >
> > {
> >         if (is.na(v[i])==FALSE & is.null(unlist(v[i]))==FALSE)
> >         {
> >                 iotw(v,leftchild(i))
> >                 print(v[i]) # return doesn't work here
> >                 iotw(v,rightchild(i))
> >         }
> > }
> 
> Shouldn't you return:
> 
> c(iotw(v, leftchild(i)), v[i], iotw(v, rightchild(i)))
> 
> (and rewrite the conditition to return null if the node doesn't exist,
> I think it reads clearer that way)
> 
> Hadley
>