BUG: value_counts / shift not in groupby dispatch whitelist (0.12-dev)

[gdraps]

Copying comment from #4887 to a new issue for discussion purposes:

While testing pandas-master, hit a method not in the new groupby dispatch whitelist: value_counts (on a SeriesGroupBy object). Another possible addition: shift, as used in this SO answer.

Tried to generate a list of blacklisted methods for DataFrame and Series, see below -- needs further filtering, but may reveal useful blocked methods. any thoughts on the remaining methods?

In [18]: sorted([x for x in set(dir(pd.DataFrame)) - pd.core.groupby._apply_whitelist - set(dir(pd.core.groupby.GroupBy)) if not x.startswith(('_', 'T', 'to', 'from', 'as'))])
Out[18]: ['abs', 'add', 'add_prefix', 'add_suffix', 'align', 'all', 'any', 'append', 'applymap', 'at', 'at_time', 'axes', 'between_time', 'bfill', 'blocks', 'bool', 'clip', 'clip_lower', 'clip_upper', 'columns', 'combine', 'combineAdd', 'combineMult', 'combine_first', 'compound', 'consolidate', 'convert_objects', 'copy', 'corr', 'corrwith', 'cov', 'delevel', 'diff', 'div', 'divide', 'dot', 'drop', 'drop_duplicates', 'dropna', 'dtypes', 'duplicated', 'empty', 'eq', 'eval', 'ffill', 'filter', 'first_valid_index', 'floordiv', 'ftypes', 'ge', 'get', 'get_dtype_counts', 'get_ftype_counts', 'get_value', 'get_values', 'groupby', 'gt', 'iat', 'icol', 'idxmax', 'idxmin', 'iget_value', 'iloc', 'index', 'info', 'insert', 'interpolate', 'irow', 'isin', 'isnull', 'iteritems', 'iterkv', 'iterrows', 'itertuples', 'ix', 'join', 'keys', 'kurt', 'kurtosis', 'last_valid_index', 'le', 'load', 'loc', 'lookup', 'lt', 'mad', 'mask', 'merge', 'mod', 'mode', 'mul', 'multiply', 'ndim', 'ne', 'notnull', 'pct_change', 'pivot', 'pivot_table', 'pop', 'pow', 'product', 'query', 'radd', 'rdiv', 'reindex', 'reindex_axis', 'reindex_like', 'rename', 'rename_axis', 'reorder_levels', 'replace', 'reset_index', 'rfloordiv', 'rmod', 'rmul', 'rpow', 'rsub', 'rtruediv', 'save', 'select', 'set_index', 'set_value', 'shape', 'shift', 'skew', 'sort', 'sort_index', 'sortlevel', 'squeeze', 'stack', 'sub', 'subtract', 'swapaxes', 'swaplevel', 'take', 'transpose', 'truediv', 'truncate', 'tshift', 'tz_convert', 'tz_localize', 'unstack', 'update', 'values', 'where', 'xs']

In [19]: sorted([x for x in set(dir(pd.Series)) - pd.core.groupby._apply_whitelist - set(dir(pd.core.groupby.GroupBy)) if not x.startswith(('_', 'T', 'to', 'from', 'as'))]) 
Out[19]: ['abs', 'add', 'add_prefix', 'add_suffix', 'align', 'all', 'any', 'append', 'argmax', 'argmin', 'argsort', 'at', 'at_time', 'autocorr', 'axes', 'base', 'between', 'between_time', 'bfill', 'blocks', 'bool', 'clip', 'clip_lower', 'clip_upper', 'combine', 'combine_first', 'compound', 'consolidate', 'convert_objects', 'copy', 'corr', 'cov', 'data', 'diff', 'div', 'divide', 'dot', 'drop', 'drop_duplicates', 'dropna', 'duplicated', 'empty', 'eq', 'ffill', 'filter', 'first_valid_index', 'flags', 'floordiv', 'ftype', 'ge', 'get', 'get_dtype_counts', 'get_ftype_counts', 'get_value', 'get_values', 'groupby', 'gt', 'iat', 'idxmax', 'idxmin', 'iget', 'iget_value', 'iloc', 'imag', 'index', 'interpolate', 'irow', 'is_time_series', 'isin', 'isnull', 'item', 'iteritems', 'iterkv', 'ix', 'keys', 'kurt', 'kurtosis', 'last_valid_index', 'le', 'load', 'loc', 'lt', 'mad', 'map', 'mask', 'mod', 'mode', 'mul', 'multiply', 'ndim', 'ne', 'nonzero', 'notnull', 'nunique', 'order', 'pct_change', 'pop', 'pow', 'product', 'ptp', 'put', 'radd', 'ravel', 'rdiv', 'real', 'reindex', 'reindex_axis', 'reindex_like', 'rename', 'rename_axis', 'reorder_levels', 'repeat', 'replace', 'reset_index', 'reshape', 'rfloordiv', 'rmod', 'rmul', 'round', 'rpow', 'rsub', 'rtruediv', 'save', 'select', 'set_value', 'shape', 'shift', 'skew', 'sort', 'sort_index', 'sortlevel', 'squeeze', 'str', 'strides', 'sub', 'subtract', 'swapaxes', 'swaplevel', 'take', 'transpose', 'truediv', 'truncate', 'tshift', 'tz_convert', 'tz_localize', 'unique', 'unstack', 'update', 'valid', 'value_counts', 'values', 'view', 'weekday', 'where', 'xs']

[jtratner]

This seems like a good idea - would be nice to get a pull-request with tests that exercise the methods that we're readding.

[jreback]

you can of course use apply and use whatever methods u want

this magic of operating on the groupby is only for convience (and possibly cythonized methods)

[gdraps]

That's fair and the exception is clear about using apply instead. Just wanted to file this as it broke existing code without a deprecation warning.

[jtratner]

@jreback wouldn't be too hard to set up a DeprecationWarning for this...

   def _make_wrapper(self, name):
        if name not in _apply_whitelist:
            is_callable = callable(getattr(self.obj, name, None))
            kind = ' callable ' if is_callable else ' '
            warn("access to{0}attribute {1!r} of {2!r} objects is deprecated"
                 " and will be removed in a future version, try using the"
                 "'apply' method".format(kind, name, type(self).__name__))

[jtratner]

@jreback I think we need to do the deprecation first, otherwise people are going to get confused. Are you okay with that?

[jreback]

sure.. (though i would add shift/value_counts to whitelist as well).

only thing with deprecation - i think it needs to be dynamic to avoid having the tab completion (the dir find those methods)

[jtratner]

We could keep the whitelist for dir completions and then use the warning if
something isn't in the whitelist, right?

[jreback]

irc their is some kind of message their now.?

[jtratner]

It's an error though right?

On Mon, Nov 11, 2013 at 5:19 PM, jreback notifications@github.com wrote:

irc their is some kind of message their now.?

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/5480#issuecomment-28245457
.

[jreback]

i am confused now

that error message is already there

i would just add shift and value_counts. not big on other methoods as they should be in the inner apply anyhow (their may be some more exception)....but I think its beter to err on the side of a limited whitelist

[jreback]

its an AttributeError which is correct, not a Deprecation.....

its more explicit to use apply

[jtratner]

I think @gdraps brought this up not only for value_counts/shift, but also because there are probably a few people who relied on some part of this and will be surprised their existing code doesn't work (even if it was buggy/wrong - @gdraps please correct me if I've mischaracterized). We generally deprecate everything before removing it, seems like that's relevant here too.

[jreback]

ok with the deprecation

but u then may need a blacklist that raises for sure - eg to_csv and such

[jtratner]

Okay, @gdraps, do you have time to put this together?

[gdraps]

I took a stab at reviewing the full list of methods and would propose the following be added to the whitelist:

'value_counts',
'mad', 'median',
'any', 'all',
'irow', 'take',
'shift', 'tshift',
'ffill', 'bfill',
'pct_change', 'skew',

As far as the blacklist goes, am thinking all to_* methods:

'to_clipboard', 'to_csv', 'to_dense', 'to_dict', 'to_excel', 'to_frame',
'to_gbq', 'to_hdf', 'to_html', 'to_json', 'to_latex', 'to_msgpack',
'to_panel', 'to_period', 'to_pickle', 'to_records', 'to_sparse', 'to_sql',
'to_stata', 'to_string', 'to_timestamp', 'to_wide',

When's the target for 0.13? I can put a PR later this week.