試圖在 pandas 中平均替換年齡，我該怎么做？

Question

df.head()

給出：

Record ID   Agency Code Agency Name Agency Type City    State   Year    Month   Incident    Crime Type  ... Victim Ethnicity    Perpetrator Sex Perpetrator Age Perpetrator Race    Perpetrator Ethnicity   Relationship    Weapon  Victim Count    Perpetrator Count   Record Source
0   1   AK00101 Anchorage   Municipal Police    Anchorage   Alaska  1980    January 1   Murder or Manslaughter  ... Unknown Male    15  Native American/Alaska Native   Unknown Acquaintance    Blunt Object    0   0   FBI
1   2   AK00101 Anchorage   Municipal Police    Anchorage   Alaska  1980    March   1   Murder or Manslaughter  ... Unknown Male    42  White   Unknown Acquaintance    Strangulation   0   0   FBI
2   3   AK00101 Anchorage   Municipal Police    Anchorage   Alaska  1980    March   2   Murder or Manslaughter  ... Unknown Unknown 0   Unknown Unknown Unknown Unknown 0   0   FBI
3   4   AK00101 Anchorage   Municipal Police    Anchorage   Alaska  1980    April   1   Murder or Manslaughter  ... Unknown Male    42  White   Unknown Acquaintance    Strangulation   0   0   FBI
4   5   AK00101 Anchorage   Municipal Police    Anchorage   Alaska  1980    April   2   Murder or Manslaughter  ... Unknown Unknown 0   Unknown Unknown Unknown Unknown 0   1   FBI

df.loc(df['Perpetrator Age']< 5)['Perpetrator Age'] = df['Perpetrator age'].mean()

給出：

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-38-8799b2e024ea> in <module>()
----> 1 df.loc(df['Perpetrator Age']< 5)['Perpetrator Age'] = df['Perpetrator Age'].mean()

c:\python27\lib\site-packages\pandas\core\indexing.pyc in __call__(self, axis)
    100 
    101         if axis is not None:
--> 102             axis = self.obj._get_axis_number(axis)
    103         new_self.axis = axis
    104         return new_self

c:\python27\lib\site-packages\pandas\core\generic.pyc in _get_axis_number(cls, axis)
    349     @classmethod
    350     def _get_axis_number(cls, axis):
--> 351         axis = cls._AXIS_ALIASES.get(axis, axis)
    352         if is_integer(axis):
    353             if axis in cls._AXIS_NAMES:

c:\python27\lib\site-packages\pandas\core\generic.pyc in __hash__(self)
   1814     def __hash__(self):
   1815         raise TypeError('{0!r} objects are mutable, thus they cannot be'
-> 1816                         ' hashed'.format(self.__class__.__name__))
   1817 
   1818     def __iter__(self):

TypeError: 'Series' objects are mutable, thus they cannot be hashed

Answer 1

嘗試

df['Perpetrator Age'][df['Perpetrator Age'] < 5] = df['Perpetrator Age'].mean()

Answer 2

使用DataFrame.loc來防止SettingWithCopyWarning與掩碼和列進行替換：

df.loc[df['Perpetrator Age'] < 5, 'Perpetrator Age'] = df['Perpetrator Age'].mean()