我想遍历数据框中的组。这在熊猫中是可能的，但是当我将它移植到考拉时，我得到一个错误。
import databricks.koalas as ks
import pandas as pd
pdf = pd.DataFrame({'x':range(3), 'y':['a','b','b'], 'z':['a','b','b']})
# Create a Koalas DataFrame from pandas DataFrame
df = ks.from_pandas(pdf)
for a in df.groupby('x'):
print(a)
这是错误：
---------------------------------------------------------------------------
KeyError Traceback (most recent call last)
<ipython-input-35-d4164d1f71e0> in <module>
----> 1 for a in df.groupby('x'):
2 print(a)
/opt/conda/lib/python3.7/site-packages/databricks/koalas/groupby.py in __getitem__(self, item)
2630 if self._as_index and is_name_like_value(item):
2631 return SeriesGroupBy(
-> 2632 self._kdf._kser_for(item if is_name_like_tuple(item) else (item,)),
2633 self._groupkeys,
2634 dropna=self._dropna,
/opt/conda/lib/python3.7/site-packages/databricks/koalas/frame.py in _kser_for(self, label)
721 Name: id, dtype: int64
722 """
--> 723 return self._ksers[label]
724
725 def _apply_series_op(self, op, should_resolve: bool = False):
KeyError: (0,)
这种群体迭代在考拉中是否可行？考拉文档有点暗示这是可能的 - https://koalas.readthedocs.io/en/latest/reference/groupby.html