[Python learning] Operator overload

• refer: https://overiq.com/python/3.4/operator-overloading-in-python/

Python可以复写 操作符 比如想要复写 +, 就在类中复写对应的 add 就可以了

Operator | Special Method | Description -- | -- |

•    | __add__(self, object)		| Addition
  

•    | __sub__(self, object)		| Subtraction
  

•    | __mul__(self, object)		| Multiplication
  

** | pow(self, object) | Exponentiation / | truediv(self, object) | Division // | floordiv(self, object) | Integer Division % | mod(self, object) | Modulus == | eq(self, object) | Equal to != | ne(self, object) | Not equal to

   | __gt__(self, object)			| Greater than

= | ge(self, object) | Greater than or equal to < | lt(self, object) | Less than <= | le(self, object) | Less than or equal to in | contains(self, value) | Membership operator [index] | getitem(self, index) | Item at index len() | len(self) | Calculate number of items str() | str(self) | Convert object to a string