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我正在嘗試計算列上的組的中值。我發現了一個很明顯的例子，在熊貓計算列上的組的中值
Pandas: Calculate Median of Group over Columns
這個問題和答案是正是我所需要的答案。我創建貼通過細節上的工作確切比如我自己
import pandas
import numpy
data_3 = [2,3,4,5,4,2]
data_4 = [0,1,2,3,4,2]
df = pandas.DataFrame({'COL1': ['A','A','A','A','B','B'],
'COL2': ['AA','AA','BB','BB','BB','BB'],
'COL3': data_3,
'COL4': data_4})
m = df.groupby(['COL1', 'COL2'])[['COL3','COL4']].apply(numpy.median)
當我嘗試了我遇到的錯誤
TypeError: Series.name must be a hashable type
列計算組的中位數。如果我做同樣的代碼唯一的區別是用不同的統計數據（平均數，最小數，最大數，標準差）代替中位數，並且一切正常。
我不明白這個錯誤的原因，爲什麼它只出現在中位數，這是我真正需要計算。
預先感謝您的幫助，
鮑勃
以下是完整的錯誤消息。我正在使用python 3.5.2
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-12-af0ef7da3347> in <module>()
----> 1 m = df.groupby(['COL1', 'COL2'])[['COL3','COL4']].apply(numpy.median)
/Applications/anaconda3/lib/python3.5/site-packages/pandas/core/groupby.py in apply(self, func, *args, **kwargs)
649 # ignore SettingWithCopy here in case the user mutates
650 with option_context('mode.chained_assignment', None):
--> 651 return self._python_apply_general(f)
652
653 def _python_apply_general(self, f):
/Applications/anaconda3/lib/python3.5/site-packages/pandas/core/groupby.py in _python_apply_general(self, f)
658 keys,
659 values,
--> 660 not_indexed_same=mutated or self.mutated)
661
662 def _iterate_slices(self):
/Applications/anaconda3/lib/python3.5/site-packages/pandas/core/groupby.py in _wrap_applied_output(self, keys, values, not_indexed_same)
3373 coerce = True if any([isinstance(x, Timestamp)
3374 for x in values]) else False
-> 3375 return (Series(values, index=key_index, name=self.name)
3376 ._convert(datetime=True,
3377 coerce=coerce))
/Applications/anaconda3/lib/python3.5/site-packages/pandas/core/series.py in __init__(self, data, index, dtype, name, copy, fastpath)
231 generic.NDFrame.__init__(self, data, fastpath=True)
232
--> 233 self.name = name
234 self._set_axis(0, index, fastpath=True)
235
/Applications/anaconda3/lib/python3.5/site-packages/pandas/core/generic.py in __setattr__(self, name, value)
2692 object.__setattr__(self, name, value)
2693 elif name in self._metadata:
-> 2694 object.__setattr__(self, name, value)
2695 else:
2696 try:
/Applications/anaconda3/lib/python3.5/site-packages/pandas/core/series.py in name(self, value)
307 def name(self, value):
308 if value is not None and not com.is_hashable(value):
--> 309 raise TypeError('Series.name must be a hashable type')
310 object.__setattr__(self, '_name', value)
311
TypeError: Series.name must be a hashable type
您是否有偶數個值？ – CodeCupboard