[R] Fwd: filter out many data.frames

[Christian Schulz]

Yes, i have recognized my stupid approach.
Now it works but any help how i get
the names in tList from the expand.grid combinaton's instead
number from 1:64 would like great!

Thanks Christian



data <- expand.grid(class02 = c("A","B","C","D"), class04 = 
c("A","B","C","D"),PREDICT = c("A","B","C","D"))
tList  <- vector("list", numeric(length(data)))

tasign <- paste("tList[[n]]  <-   try(summary(dtree[dtree$class02 == 
paste(data$class02[n]) & dtree$class04 == paste(data$class04[n]) & 
dtree$PREDICT==paste(data$PREDICT[n]),]))")
tasign <-  parse(text=tasign)[[1]]
          
for(n in 1:nrow(data)) {
  TAsign <- do.call("substitute",list(tasign,list(n=n,X=as.name(n))))
  eval(TAsign)
}




Am Sonntag, 16. Mai 2004 12:48 schrieb Uwe Ligges:
> Christian Schulz wrote:
> >   X <- numeric(length(data.frame))
> > before the loop maybe work, because
> > my computer works and works !?
> >
> > christian
> >
> >
> > ----------  Weitergeleitete Nachricht  ----------
> >
> > Subject: filter out many data.frames
> > Date: Sonntag, 16. Mai 2004 00:02
> > From: Christian Schulz <ozric at web.de>
> > To: r-help at stat.math.ethz.ch
> >
> > Hi ,
> >
> > i would like  filter out all combinations of a  data-mining result?
> > How i have to declare X because in every loop step it have another
> > lengths ?
> >
> >   X <- numeric(length(i1,...,i64))  ?
> >
> > Many thanks
> > Christian
> >
> >
> >  tres <- function(data.frame) {
> > + data <- expand.grid(class02 = c("A","B","C","D"), class04 =
> > c("A","B","C","D"),PREDICT = c("A","B","C","D"))
> > +     for (i in 1:nrow(data)){
> > +     X[i]<- dtree[dtree$class02 == paste(data$class02[i]) &
> > dtree$class04 == paste(data$class04[i]) &
> > dtree$PREDICT==paste(data$PREDICT[i]),] +     }
> > +     return(X[i])
> > +     }
>
> Eh. You really want to rewrite that code. It depends on objects
> available in its parent (or grand-parent) envrionment.
> I don't see why you need all those calls to paste().
> You do *not* want to call an argument data.frame nor any other object
> data, but you *do* want to use the arguments specified.
>
> Now, if X is initialized with numeric(), X is a numeric (n x 1) vector.
> I think you need at least a matrix or better a list, if the subsetting
> stuff returns more or even less than one row.
>
> For a list X use, e.g.,
>   X <- vector(nrow(data), mode = "list")
> just before the for loop.
>
> Uwe Ligges
>
> >> tres(dtree)
> >
> > Error: Object "X" not found
> >
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