[R] problems with for: warnings and segfault

Peter Dalgaard p.dalgaard at biostat.ku.dk
Fri Nov 11 16:34:10 CET 2005

```"Ronaldo Reis-Jr." <chrysopa at gmail.com> writes:

> Hi,
>
> I have two problem with a for looping using R Version 2.1.1  (2005-06-20) on a
> Debian Linux Testing.
>
> The first problem: warnings messages
>
> Look:
>
> > xcoord <- 5
> > ycoord <- 5
> > indice <- 1
> > for(i in c(1:5)) {indice <- indice+1;xcoord[indice] <- xcoord+i;
> ycoord[indice] <- ycoord }
> Warning messages:
> 1: number of items to replace is not a multiple of replacement length
> 2: number of items to replace is not a multiple of replacement length
> 3: number of items to replace is not a multiple of replacement length
> 4: number of items to replace is not a multiple of replacement length
> 5: number of items to replace is not a multiple of replacement length
> 6: number of items to replace is not a multiple of replacement length
> 7: number of items to replace is not a multiple of replacement length
> 8: number of items to replace is not a multiple of replacement length
>
> > xcoord
> [1]  5  6  7  8  9 10
> > ycoord
> [1] 5 5 5 5 5 5
> >
>
> The results are OK, but I dont understand the warning message

Look at

xcoord[indice] <- xcoord+i

The left hand side is a single element, the right hand side is a
vector so I don't think it means what I think you think it means.

> The second problem: The segfault
>
> > xcoord <- 5
> > ycoord <- 5
> > indice <- 1
> > for(i in c(1:100)) {indice <- indice+1;xcoord[indice] <- xcoord+i;
> ycoord[indice] <- ycoord }
> Segmentation fault
>
> This is a R bug or an error in my for function?

R shouldn't segfault no matter how silly the code....

[I see this on 2.2.0/Linux too, on the 2nd try of the for loop]

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```