我最近在python中了解了运算符重载，我想知道以下是否可行。
考虑下面的hypothetica /设法类。
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
我知道上面写的方式，我可以做这样的事情
n1 = My_Num(1)
n2 = My_Num(2)
n3 = 3
print n1 + n2
print n1 + n3
这些将按预期工作。我也知道它目前写的方式我不能这样做
n1 = My_Num(1)
n2 = 2
print 2 + n1
有没有办法解决？我知道这个例子是设计的，但我有一个应用程序，如果我在运算符重载时，它非常有用，我定义运算符的类可以出现在运算符的右侧。这在python中可行吗？
是。例如，有 __radd__。也， 没有了 对于 __le__()， __ge__()等等，但正如Joel Cornett正确观察到的那样，如果你只定义 __lt__， a > b 打电话给 __lt__ 的功能 b，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 + n1
4
>>> print n1 + n2
Traceback (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，执行以下操作是合理的：
>>> 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__
是。例如，有 __radd__。也， 没有了 对于 __le__()， __ge__()等等，但正如Joel Cornett正确观察到的那样，如果你只定义 __lt__， a > b 打电话给 __lt__ 的功能 b，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 + n1
4
>>> print n1 + n2
Traceback (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，执行以下操作是合理的：
>>> 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__
你必须超载 __radd__ 方法（右侧添加）。你的功能看起来和你的功能差不多 __add__ 方法，例如：
def __radd__(self, other):
return self.val + other.val