[R] Unexpected behaviour as.data.frame

[Jan van der Laan]

Forget I asked. There was a typo in my example (stringsAsFactor  
instead of stringAsFactors) which explained the difference. My  
apologies.

My second question however still stands: How does on create a  
data.frame with given column types and given dimensions? Thanks.

Regards,
Jan


Quoting Jan van der Laan <rhelp at eoos.dds.nl>:

> 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