在运行时向Numpy数组添加属性

问题描述

我正在尝试使用setattr将属性添加到Numpy ndarray，但收到错误：

import numpy as np

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

AttributeError：numpy.ndarray对象没有属性new_attr

如何向Numpy ndarray添加新属性？

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解决方案

使用您的示例并参考Simple example - adding an extra attribute to ndarray，您可以做的事情是

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)

然后

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

或直接在实例化时

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