Python 子类化数据帧，更新？

继承还是不继承

熊猫子类化问题的最新进展是什么？（大多数其他螺纹的使用年限为3-4年）

我希望做一些像

import pandas as pd

class SomeData(pd.DataFrame):
    # Methods
    pass

ClsInstance = SomeData()

# Create a new column on ClsInstance?

---

我就是这样做的。我听从了建议，发现：

下面的示例仅显示了如何构造

pandas.DataFrame

的新子类。如果你遵循我的第一个链接的建议，你可以考虑子类<代码>熊猫。系列< /代码>也解释了你的代码<熊猫>的一维切片。数据文件子类。

定义

SomeData

---

示范

---

你可以这样做，但那之后你到底想做什么

import pandas as pd
import numpy as np

class SomeData(pd.DataFrame):
    # This class variable tells Pandas the name of the attributes
    # that are to be ported over to derivative DataFrames.  There
    # is a method named `__finalize__` that grabs these attributes
    # and assigns them to newly created `SomeData`
    _metadata = ['my_attr']

    @property
    def _constructor(self):
        """This is the key to letting Pandas know how to keep
        derivative `SomeData` the same type as yours.  It should
        be enough to return the name of the Class.  However, in
        some cases, `__finalize__` is not called and `my_attr` is
        not carried over.  We can fix that by constructing a callable
        that makes sure to call `__finlaize__` every time."""
        def _c(*args, **kwargs):
            return SomeData(*args, **kwargs).__finalize__(self)
        return _c

    def __init__(self, *args, **kwargs):
        # grab the keyword argument that is supposed to be my_attr
        self.my_attr = kwargs.pop('my_attr', None)
        super().__init__(*args, **kwargs)

    def my_method(self, other):
        return self * np.sign(self - other)

mydata = SomeData(dict(A=[1, 2, 3], B=[4, 5, 6]), my_attr='an attr')

print(mydata, type(mydata), mydata.my_attr, sep='\n' * 2)

   A  B
0  1  4
1  2  5
2  3  6

<class '__main__.SomeData'>

an attr

newdata = mydata.mul(2)

print(newdata, type(newdata), newdata.my_attr, sep='\n' * 2)

   A   B
0  2   8
1  4  10
2  6  12

<class '__main__.SomeData'>

an attr

newerdata = mydata.my_method(newdata)

print(newerdata, type(newerdata), newerdata.my_attr, sep='\n' * 2)

   A  B
0 -1 -4
1 -2 -5
2 -3 -6

<class '__main__.SomeData'>

an attr

newerdata.equals(newdata)  # Should be `False`

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-304-866170ab179e> in <module>()
----> 1 newerdata.equals(newdata)

~/anaconda3/envs/3.6.ml/lib/python3.6/site-packages/pandas/core/generic.py in equals(self, other)
   1034         the same location are considered equal.
   1035         """
-> 1036         if not isinstance(other, self._constructor):
   1037             return False
   1038         return self._data.equals(other._data)

TypeError: isinstance() arg 2 must be a type or tuple of types

    def equals(self, other):
        try:
            pd.testing.assert_frame_equal(self, other)
            return True
        except AssertionError:
            return False

newerdata.equals(newdata)  # Should be `False`

False