[R] Setting Values of Elements in a Dataframe

[Ivan Calandra]

Hi,

Not sure why it doesn't work (I would say it's because of the structure 
of sel_pos, but I don't know how to deal with it).

But just do:
d[d>0] <- -9
It does work

HTH,
Ivan

Le 11/29/2010 16:56, Lorenzo Isella a écrit :
> Dear All,
> I am experiencing some problems in resetting the values of some 
> selected elements in a dataframe.
>
> Consider
>
>
> d<-seq(-1,1,length=16)
> dim(d)<-c(4,4)
> d<-as.data.frame(d)
>
> sel_pos<-which(d>0, arr.ind=TRUE)
>
> d[sel_pos]<- -9
>
> which returns the error
>
> Error in `[<-.data.frame`(`*tmp*`, sel_pos, value = -9) :
>   only logical matrix subscripts are allowed in replacement
>
> which is obscure to me. I am correctly selecting the positive elements 
> in a data.frame and I'd like to reset them to another numerical value.
> What I am misunderstanding?
> Many thanks
>
> Lorenzo
>
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-- 
Ivan CALANDRA
PhD Student
University of Hamburg
Biozentrum Grindel und Zoologisches Museum
Abt. Säugetiere
Martin-Luther-King-Platz 3
D-20146 Hamburg, GERMANY
+49(0)40 42838 6231
ivan.calandra at uni-hamburg.de

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