[Rd] Behavior of seq_along (was: Create a new var reflecting the order of subjects in existing var)

[Gabor Grothendieck]

Good point.  I tried it on

"R version 2.5.0 Under development (unstable) (2007-02-25 r40804)"

under Windows XP and both the seq_along and function(x) seq_along(x)
versions worked without error, as well.

So it seems this was a bug in 2.4.1 that is fixed in 2.5.0 .

On 4/3/07, Benilton Carvalho <bcarvalh at jhsph.edu> wrote:
> I'm not sure what your sessionInfo() is, but take a look at what I got:
>
>  > set.seed(123)
>  > dat <- data.frame(ID= c(rep(1,2),rep(2,3), rep(3,3), rep(4,4),
> +    rep(5,5)), var1 =rnorm(17, 35,2), var2=runif(17,0,1))
>  > dat
>    ID     var1       var2
> 1   1 33.87905 0.02461368
> 2   1 34.53965 0.47779597
> 3   2 38.11742 0.75845954
> 4   2 35.14102 0.21640794
> 5   2 35.25858 0.31818101
> 6   3 38.43013 0.23162579
> 7   3 35.92183 0.14280002
> 8   3 32.46988 0.41454634
> 9   4 33.62629 0.41372433
> 10  4 34.10868 0.36884545
> 11  4 37.44816 0.15244475
> 12  4 35.71963 0.13880606
> 13  5 35.80154 0.23303410
> 14  5 35.22137 0.46596245
> 15  5 33.88832 0.26597264
> 16  5 38.57383 0.85782772
> 17  5 35.99570 0.04583117
>  > ave(dat$ID, dat$ID, FUN = function(x) seq_along(x))
> [1] 1 2 1 2 3 1 2 3 1 2 3 4 1 2 3 4 5
>  > ave(dat$ID, dat$ID, FUN = seq_along)
> [1] 1 2 1 2 3 1 2 3 1 2 3 4 1 2 3 4 5
>  > sessionInfo()
> R version 2.5.0 Under development (unstable) (2007-01-07 r40398)
> x86_64-unknown-linux-gnu
>
> locale:
> LC_CTYPE=en_US.iso885915;LC_NUMERIC=C;LC_TIME=en_US.iso885915;LC_COLLATE
> =en_US.iso885915;LC_MONETARY=en_US.iso885915;LC_MESSAGES=en_US.iso885915
> ;LC_PAPER=en_US.iso885915;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASU
> REMENT=en_US.iso885915;LC_IDENTIFICATION=C
>
> attached base packages:
> [1] "stats"     "graphics"  "grDevices" "utils"     "datasets"
> "methods"
> [7] "base"
>  >
>
> cheers,
> b
>
> On Apr 3, 2007, at 12:40 AM, Gabor Grothendieck wrote:
>
> > I am moving this from r-help to r-devel.  Based on offline
> > communications
> > with Jim, suppose dat is defined as follows:
> >
> > set.seed(123)
> > dat <- data.frame(ID= c(rep(1,2),rep(2,3), rep(3,3), rep(4,4),
> >    rep(5,5)), var1 =rnorm(17, 35,2), var2=runif(17,0,1))
> >
> > # Then this ave call works as expected:
> >
> > ave(dat$ID, dat$ID, FUN = function(x) seq_along(x))
> >
> > # but this apparently identical calculation gives an error:
> >
> > ave(dat$ID, dat$ID, FUN = seq_along)
> >
> > The only difference between the two calls is that the first one
> > uses seq_along and the second uses function(x) seq_along(x)
> > in its place.
> >
> > Does anyone know why the second gives an error?  Is this
> > a bug in the implementation of seq_along?
> >
> > ______________________________________________
> > R-devel at r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-devel
>