ddf.groupby("A").fillna(0, axis=1)
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
~/mambaforge/envs/dask-dev/lib/python3.9/site-packages/pandas/core/generic.py in _get_axis_number(cls, axis)
    545         try:
--> 546             return cls._AXIS_TO_AXIS_NUMBER[axis]
    547         except KeyError:

KeyError: 1

During handling of the above exception, another exception occurred:

ValueError                                Traceback (most recent call last)
~/mambaforge/envs/dask-dev/lib/python3.9/site-packages/pandas/core/groupby/generic.py in _transform_general(self, func, *args, **kwargs)
   1316             try:
-> 1317                 path, res = self._choose_path(fast_path, slow_path, group)
   1318             except TypeError:

~/mambaforge/envs/dask-dev/lib/python3.9/site-packages/pandas/core/groupby/generic.py in _choose_path(self, fast_path, slow_path, group)
   1393         path = slow_path
-> 1394         res = slow_path(group)
   1395 

~/mambaforge/envs/dask-dev/lib/python3.9/site-packages/pandas/core/groupby/generic.py in <lambda>(group)
   1386             fast_path = lambda group: func(group, *args, **kwargs)
-> 1387             slow_path = lambda group: group.apply(
   1388                 lambda x: func(x, *args, **kwargs), axis=self.axis

~/mambaforge/envs/dask-dev/lib/python3.9/site-packages/pandas/core/frame.py in apply(self, func, axis, raw, result_type, args, **kwargs)
   8739         )
-> 8740         return op.apply()
   8741 

~/mambaforge/envs/dask-dev/lib/python3.9/site-packages/pandas/core/apply.py in apply(self)
    687 
--> 688         return self.apply_standard()
    689 

~/mambaforge/envs/dask-dev/lib/python3.9/site-packages/pandas/core/apply.py in apply_standard(self)
    811     def apply_standard(self):
--> 812         results, res_index = self.apply_series_generator()
    813 

~/mambaforge/envs/dask-dev/lib/python3.9/site-packages/pandas/core/apply.py in apply_series_generator(self)
    827                 # ignore SettingWithCopy here in case the user mutates
--> 828                 results[i] = self.f(v)
    829                 if isinstance(results[i], ABCSeries):

~/mambaforge/envs/dask-dev/lib/python3.9/site-packages/pandas/core/groupby/generic.py in <lambda>(x)
   1387             slow_path = lambda group: group.apply(
-> 1388                 lambda x: func(x, *args, **kwargs), axis=self.axis
   1389             )

~/Developer/Dask/dask/dask/dataframe/groupby.py in _fillna_groups(self, groups, **kwargs)
   1987     def _fillna_groups(self, groups, **kwargs):
-> 1988         return groups.fillna(**kwargs)
   1989 

~/mambaforge/envs/dask-dev/lib/python3.9/site-packages/pandas/util/_decorators.py in wrapper(*args, **kwargs)
    310                 )
--> 311             return func(*args, **kwargs)
    312 

~/mambaforge/envs/dask-dev/lib/python3.9/site-packages/pandas/core/series.py in fillna(self, value, method, axis, inplace, limit, downcast)
   4815     ) -> Series | None:
-> 4816         return super().fillna(
   4817             value=value,

~/mambaforge/envs/dask-dev/lib/python3.9/site-packages/pandas/core/generic.py in fillna(self, value, method, axis, inplace, limit, downcast)
   6320             axis = 0
-> 6321         axis = self._get_axis_number(axis)
   6322 

~/mambaforge/envs/dask-dev/lib/python3.9/site-packages/pandas/core/generic.py in _get_axis_number(cls, axis)
    547         except KeyError:
--> 548             raise ValueError(f"No axis named {axis} for object type {cls.__name__}")
    549 

ValueError: No axis named 1 for object type Series

The above exception was the direct cause of the following exception:

ValueError                                Traceback (most recent call last)
<ipython-input-4-f9b1a98697a0> in <module>
----> 1 ddf.groupby("A").fillna(0, axis=1)

~/Developer/Dask/dask/dask/dataframe/groupby.py in fillna(self, value, method, limit, axis)
   1993                 "groupby-fillna with value=dict/Series/DataFrame is currently not supported"
   1994             )
-> 1995         meta = self._meta_nonempty.transform(
   1996             self._fillna_groups, value=value, method=method, limit=limit, axis=axis
   1997         )

~/mambaforge/envs/dask-dev/lib/python3.9/site-packages/pandas/core/groupby/generic.py in transform(self, func, engine, engine_kwargs, *args, **kwargs)
   1355     @Appender(_transform_template)
   1356     def transform(self, func, *args, engine=None, engine_kwargs=None, **kwargs):
-> 1357         return self._transform(
   1358             func, *args, engine=engine, engine_kwargs=engine_kwargs, **kwargs
   1359         )

~/mambaforge/envs/dask-dev/lib/python3.9/site-packages/pandas/core/groupby/groupby.py in _transform(self, func, engine, engine_kwargs, *args, **kwargs)
   1444 
   1445         if not isinstance(func, str):
-> 1446             return self._transform_general(func, *args, **kwargs)
   1447 
   1448         elif func not in base.transform_kernel_allowlist:

~/mambaforge/envs/dask-dev/lib/python3.9/site-packages/pandas/core/groupby/generic.py in _transform_general(self, func, *args, **kwargs)
   1320             except ValueError as err:
   1321                 msg = "transform must return a scalar value for each group"
-> 1322                 raise ValueError(msg) from err
   1323 
   1324             if isinstance(res, Series):

ValueError: transform must return a scalar value for each group