On Sat, Sep 17, 2011 at 5:12 PM, Wes McKinney <wesmck...@gmail.com> wrote: > On Sat, Sep 17, 2011 at 4:48 PM, Skipper Seabold <jsseab...@gmail.com> wrote: >> Just ran into this. Any objections for having numpy.std and other >> functions in core/fromnumeric.py call asanyarray before trying to use >> the array's method? Other data structures like pandas and larry define >> their own std method, for instance, and this doesn't allow them to >> pass through. I'm inclined to say that the issue is with numpy, though >> maybe the data structures shouldn't shadow numpy array methods while >> altering the signature. I dunno. >> >> df = pandas.DataFrame(np.random.random((10,5))) >> >> np.std(df,axis=0) >> <snip> >> TypeError: std() got an unexpected keyword argument 'dtype' >> >> np.std(np.asanyarray(df),axis=0) >> array([ 0.30883352, 0.3133324 , 0.26517361, 0.26389029, 0.20022444]) >> >> Though I don't think this would work with larry yet. >> >> Pull request: https://github.com/numpy/numpy/pull/160 >> >> Skipper >> _______________________________________________ >> NumPy-Discussion mailing list >> NumPy-Discussion@scipy.org >> http://mail.scipy.org/mailman/listinfo/numpy-discussion >> > > Note I've no real intention of making DataFrame fully ndarray-like-- > but it's nice to be able to type: > > df.std(axis=0) > df.std(axis=1) > np.sqrt(df) > > etc. which works the same as ndarray. I suppose the > __array__/__array_wrap__ interface is there largely as a convenience.
I'm a bit worried about the different ddof defaults in cases like this. Essentially we will not be able to rely on ddof=0 anymore. Different defaults on axis are easy to catch, but having the same function call return sometimes ddof=0 and sometimes ddof=1 might make for some fun debugging. Josef > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion > _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
