Anne Ghisla wrote:
> Hi list,
>
> I'm using packaged rpy2 on Debian Squeeze in a python-grass script to
> perform kriging and, among other things that rpy2 executes smoothly, I
> need tho change the names of two columns in a dataframe.
> This edit is necessary because the dataframe coming from previous
> as.data.frame command receives arbitrary column names.
>
> Picking up some sample code:
>
> d = {'value': robjects.IntVector((1,2,3)),
> 'letter': robjects.StrVector(('x', 'y', 'z'))}
> dataf = robjects.r['data.frame'](**d)
>
> For example, I need to change 'letter' column name into 'code'
> without modifying its content neither other columns. In R I would have
> written:
>
> names(dataf) = c("value", "code")
>
> I tried alternatively:
>
> dataf.names = robjects.r.gsub('letter','code',dataf.names)
> dataf.names = robjects.r.c('value','code')
>
> with no success. The error says that dataf.names doesn't support
> assignment. Also I didn't succeed in handling it as Python object, as
> the type is RVector.
> Gsub works when I assing the result to a copy of dataf.names.
>
> Any suggestion and link to docs/examples will be appreciated.
One of the shortcomings in rpy2.robjects v2.0.x concerns the rebinding
of underlying R objects, needed by the pass-by-value paradigm in R
(rnumpy has been working around that by using delegation rather than
inheritance). It has been fixed in rpy2-2.1dev.
Otherwise, since you want to replace the elements in a vector, the usual
__setitem__ should replace them "in-place".
suggestion:
new_names = robjects.r.gsub('letter','code',dataf.names)
for i, val in enumerate(new_names):
dataf.names[i] = val
link:
http://rpy.sourceforge.net/rpy2/doc-dev/html/robjects.html#names
HTH,
L.
> thanks in advance
> Anne
>
>
> ------------------------------------------------------------------------
>
> ------------------------------------------------------------------------------
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> rpy-list mailing list
> rpy-list@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/rpy-list
------------------------------------------------------------------------------
_______________________________________________
rpy-list mailing list
rpy-list@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/rpy-list
