[R] Thougt I understood factors but??

[Nicholas Lewin-Koh]

Hi,
consider the following
> a<-gl(3,3,9)
> a
[1] 1 1 1 2 2 2 3 3 3
Levels: 1 2 3
> levels(a)<-3:1
> a
[1] 3 3 3 2 2 2 1 1 1
Levels: 3 2 1
> a<-gl(3,3,9)
> factor(a,levels=3:1)
[1] 1 1 1 2 2 2 3 3 3
Levels: 3 2 1
It is probably something obvious I missed, but reading the documentation
of factor, and levels I would have thought
that both should produce the same output as 
factor(a,levels=3:1)
[1] 1 1 1 2 2 2 3 3 3
Levels: 3 2 1
The closest I could find in a quick search was this
http://tolstoy.newcastle.edu.au/R/e5/help/08/09/2503.html

Thanks
Nicholas

sessionInfo()
R version 2.10.1 Patched (2009-12-20 r50794) 
x86_64-unknown-linux-gnu 

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
 [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8    
 [5] LC_MONETARY=C              LC_MESSAGES=en_US.UTF-8   
 [7] LC_PAPER=en_US.UTF-8       LC_NAME=C                 
 [9] LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C    
attached base packages:
[1] splines   tcltk     stats     graphics  grDevices utils     datasets 
[8] methods   base     

other attached packages:
[1] mvtnorm_0.9-9      latticeExtra_0.6-9 RColorBrewer_1.0-2
lattice_0.18-3    
[5] nlme_3.1-96        XML_2.6-0          gsubfn_0.5-0       proto_0.3-8 

loaded via a namespace (and not attached):
[1] grid_2.10.1  tools_2.10.1