R devel - Nov 2004 - foreign(read.spss) in rw2000 and re2001beta

I encountered something strange with read.spss (package foreign, version 
0.7 with R2.0.0 and
version 0.8 with R2.0.1 beta, windows XP)

I made a test file test.sav with SPSS version 11.5.1
containing only one numeric variable, with a value label
for one value not occuring in the file. According to ?read.spss
this should result in a factor, but it results in all NA. Using the 
argument
use.value.labels=FALSE, everything is read as expected.

test <- read.spss("test.sav", to.=TRUE)
test > only NA's

Kjetil

-- 

Kjetil Halvorsen.

Peace is the most effective weapon of mass construction.
               --  Mahdi Elmandjra

On Sat, 6 Nov 2004, Kjetil Brinchmann Halvorsen wrote:
> I encountered something strange with read.spss (package foreign, version 
> 0.7 with R2.0.0 and
> version 0.8 with R2.0.1 beta, windows XP)
Please clarify: the same thing in both versions (read.spss has not changed 
between them)?
> I made a test file test.sav with SPSS version 11.5.1
> containing only one numeric variable, with a value label
> for one value not occuring in the file. According to ?read.spss
> this should result in a factor, but it results in all NA. Using the 
> argument
> use.value.labels=FALSE, everything is read as expected.
Can you make that file available please?
> test <- read.spss("test.sav", to.=TRUE)
> test > only NA's
> 
> Kjetil
> 
> 
-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

Kjetil Brinchmann Halvorsen <kjetil@acelerate.com> writes:
> I made a test file test.sav with SPSS version 11.5.1
> containing only one numeric variable, with a value label
> for one value not occuring in the file. According to ?read.spss
> this should result in a factor, but it results in all NA. 
Er, what do you mean "all NA"? If the only factor level corresponds to
a value that isn't present, wouldn't you expect to get a factor with
one level and all values missing? What does str() say about the
resulting object?

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk)             FAX: (+45) 35327907

On Sat, 6 Nov 2004, Peter Dalgaard wrote:
> Kjetil Brinchmann Halvorsen <kjetil@acelerate.com> writes:
>
>> I made a test file test.sav with SPSS version 11.5.1
>> containing only one numeric variable, with a value label
>> for one value not occuring in the file. According to ?read.spss
>> this should result in a factor, but it results in all NA.
>
It should result in a factor all of whose values are missing. And it does.

I have modified read.spss (but not committed the changes yet)  so that it 
does not create a factor when there are missing levels.

The problem is that SPSS uses value labels for two different things: for 
factors and for labelling a subset of values (eg different types of 
missing). It is hard for R to guess which the user intends.

You can always set use.value.labels=FALSE.  You still get the value labels 
read in and then you can decide what to do with them.

 	-thomas