python中的运算符重载，对象在运算符的右侧

python中的运算符重载，对象在运算符的右侧

是。例如，有

__radd__

。另外，没有用于

__le__()

，

__ge__()

等的对象，但是正如乔尔·科内特（Joel
Cornett）正确地观察到的那样，如果仅定义

__lt__

，则

a > b

调用的

__lt__

功能

b

，这提供了一种解决方法。

>>> class My_Num(object):...     def __init__(self, val):...         self.val = val...     def __radd__(self, other_num):...         if isinstance(other_num, My_Num):...  return self.val + other_num.val...         else:...  return self.val + other_num... >>> n1 = My_Num(1)>>> n2 = 3>>> >>> print n2 + n14>>> print n1 + n2Traceback (most recent call last):  File "<stdin>", line 1, in <module>TypeError: unsupported operand type(s) for +: 'My_Num' and 'int'

请注意，至少在某些情况下，这样做是合理的：

>>> class My_Num(object):...     def __init__(self, val):...         self.val = val...     def __add__(self, other_num):...         if isinstance(other_num, My_Num):...  return self.val + other_num.val...         else:...  return self.val + other_num...     __radd__ = __add__