python - 在运行时向 Numpy 数组添加属性

Question

我正在尝试使用 setattr 向 Numpy ndarray 添加属性，但出现错误:

import numpy as np

x = np.array([1, 2, 4])
setattr(x, 'new_attr', 1)

AttributeError: numpy.ndarray object has no attribute new_attr

如何向 Numpy ndarray 添加新属性？

Answer 1

使用您的示例并引用 Simple example - adding an extra attribute to ndarray ，你可以做的是

class YourArray(np.ndarray):

    def __new__(cls, input_array, your_new_attr=None):        
        obj = np.asarray(input_array).view(cls)
        obj.your_new_attr = your_new_attr
        return obj

    def __array_finalize__(self, obj):
        if obj is None: return
        self.your_new_attr = getattr(obj, 'your_new_attr', None)

进而

>>> x = np.array([1, 2, 4])
>>> x_ = YourArray(x)
>>> x_.your_new_attr = 2
>>> x_.your_new_attr
2

或直接在实例化

>>> # x_ = YourArray([1, 2, 4], your_new_attr=3) works as well
>>> x_ = YourArray(x, your_new_attr=3)
>>> x_.your_new_attr
3