[R] Unexpected behaviour as.data.frame

[Bert Gunter]

In your post, you're missing the final "s" on the stringsAsFactors
argument in the d1 assignment. When I typed it correctly, it works as
expected.

-- Bert

On Sun, May 15, 2011 at 4:25 AM, Jan van der Laan <rhelp at eoos.dds.nl> wrote:
> I use the following code to create two data.frames d1 and d2 from a list:
> types  <- c("integer", "character", "double")
> nlines <- 10
> d1     <- as.data.frame(lapply(types, do.call, list(nlines)),
> stringsAsFactor=FALSE)
> l2     <- lapply(types, do.call, list(nlines))
> d2     <- as.data.frame(l2, stringsAsFactors=FALSE)
>
> I would expect d1 and d2 to be the same, however, in d1 the second column is
> a factor while in d2 it is a character (which I would expect):
>
>> str(d1)
>
> 'data.frame':   10 obs. of  3 variables:
>  $ c.0L..0L..0L..0L..0L..0L..0L..0L..0L..0L.: int  0 0 0 0 0 0 0 0 0 0
>  $ c........................................: Factor w/ 1 level "": 1 1 1 1
> 1 1 1 1 1 1
>  $ c.0..0..0..0..0..0..0..0..0..0.          : num  0 0 0 0 0 0 0 0 0 0
>>
>> str(d2)
>
> 'data.frame':   10 obs. of  3 variables:
>  $ c.0L..0L..0L..0L..0L..0L..0L..0L..0L..0L.: int  0 0 0 0 0 0 0 0 0 0
>  $ c........................................: chr  "" "" "" "" ...
>  $ c.0..0..0..0..0..0..0..0..0..0.          : num  0 0 0 0 0 0 0 0 0 0
>
>
> As different but related question: I use the commands above to create an
> 'empty' data.frame with specified column types and dimensions. I need this
> data.frame to pass on to my c++ routines. Is there a more simple/elegant way
> of creating this data.frame?
>
> Regards,
>
> Jan
>
>
> PS:
> I am running R on 64 bit Ubuntu 11.04:
>
>> sessionInfo()
>
> R version 2.12.1 (2010-12-16)
> Platform: x86_64-pc-linux-gnu (64-bit)
>
> 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] stats     graphics  grDevices utils     datasets  methods   base
>
> ______________________________________________
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> and provide commented, minimal, self-contained, reproducible code.
>



-- 
"Men by nature long to get on to the ultimate truths, and will often
be impatient with elementary studies or fight shy of them. If it were
possible to reach the ultimate truths without the elementary studies
usually prefixed to them, these would not be preparatory studies but
superfluous diversions."

-- Maimonides (1135-1204)

Bert Gunter
Genentech Nonclinical Biostatistics
467-7374
http://devo.gene.com/groups/devo/depts/ncb/home.shtml