有没有办法让python all()函数处理多维数组?

class Environment: def __init__(self, state): self.state = state def __eq__(self, other): """Compare two environments based on their states. """ if isinstance(other, self.__class__): try: return all(self.state == other.state) except TypeError: return self.state == other.state return False

Signature: all(iterable, /)
Docstring:
Return True if bool(x) is True for all values x in the iterable.

对于一维数组:

In [200]: x=np.ones(3)                                                               
In [201]: x                                                                          
Out[201]: array([1., 1., 1.])
In [202]: y = x==x                                                                   
In [203]: y          # 1d array of booleans                                                                      
Out[203]: array([ True,  True,  True])
In [204]: bool(y[0])                                                                 
Out[204]: True
In [205]: all(y)                                                                     
Out[205]: True

对于二维数组:

In [206]: x=np.ones((2,3))                                                           
In [207]: x                                                                          
Out[207]: 
array([[1., 1., 1.],
       [1., 1., 1.]])
In [208]: y = x==x                                                                   
In [209]: y                                                                          
Out[209]: 
array([[ True,  True,  True],
       [ True,  True,  True]])
In [210]: y[0]                                                                       
Out[210]: array([ True,  True,  True])
In [211]: bool(y[0])                                                                 
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-211-d0ce0868392c> in <module>
----> 1 bool(y[0])

ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

但对于不同的二维阵列:

In [212]: x=np.ones((3,1))                                                           
In [213]: y = x==x                                                                   
In [214]: y                                                                          
Out[214]: 
array([[ True],
       [ True],
       [ True]])
In [215]: y[0]                                                                       
Out[215]: array([ True])
In [216]: bool(y[0])                                                                 
Out[216]: True
In [217]: all(y)                                                                     
Out[217]: True

对numpy数组的迭代发生在第一个维度上。 [i for i in x]

每当在需要标量布尔值的上下文中使用多值布尔值数组时,都会引发此歧义值错误。 if 和 or/and 表达式是常见的。

In [223]: x=np.ones((2,3))                                                           
In [224]: y = x==x                                                                   
In [225]: np.all(y)                                                                  
Out[225]: True

np.all 是不同的巨蟒 all 因为它“知道”尺寸。在这种情况下,它会 ravel 要将数组视为1d:

缺省值(默认值) axis = None )是对输入数组的所有维度执行逻辑和。