30-Python内置方法之__str__和__repr__
定义一个类，然后实例化，观察打印结果：
1 >>> class Person(object): 2 ... def __init__(self, name, age): 3 ... self.name = name 4 ... self.age = age 5 ... 6 >>> p = Person("druid", 18) 7 >>> p 8 <Person object at 0x11044b160> # 直接调用对象打印的是内存地址 9 >>> print(p) 10 <Person object at 0x11044b160> # 用print打印仍然是内存地址
在类中增加__str__方法，观察打印结果：
1 >>> class Person(object): 2 ... def __init__(self, name, age): 3 ... self.name = name 4 ... self.age = age 5 ... 6 ... def __str__(self): 7 ... return "{}-{}".format(self.name, self.age) 8 ... 9 >>> p1 = Person("druid", 18) 10 >>> p1 11 <Person object at 0x1105899e8> # 直接调用对象打印的是内存地址 12 >>> print(p1) 13 druid-18 # 用print打印的是__str__返回的string
在类中增加__repr__方法，观察打印结果：
1 >>> class Person(object): 2 ... def __init__(self, name, age): 3 ... self.name = name 4 ... self.age = age 5 ... 6 ... def __repr__(self): 7 ... return "{}-{}".format(self.name, self.age) 8 ... 9 >>> p2 = Person("druid", 18) 10 >>> p2 11 druid-18 # 直接调用对象打印的是__repr__返回的string 12 >>> print(p2) 13 druid-18 # 用print打印仍然是__repr__返回的string
