python进阶四：类的继承

python继承：（1）总是从某个类继承

（2）要用父类super方法进行初始化。

继承一个类 ：Teacher继承自Person类 正确调用父类的__init__方法

class Person(object):
def __init__(self, name, gender):
self.name = name
self.gender = gender

class Teacher(Person):

def __init__(self, name, gender, course):
super(Teacher,self).__init__(name,gender)
self.course=course

t = Teacher('Alice', 'Female', 'English')
print t.name
print t.course

判断 实例类型：isinstance(instance,class)

class Person(object):

def __init__(self, name, gender):
self.name = name
self.gender = gender

class Student(Person):

def __init__(self, name, gender, score):
super(Student, self).__init__(name, gender)
self.score = score

class Teacher(Person):

def __init__(self, name, gender, course):
super(Teacher, self).__init__(name, gender)
self.course = course

t = Teacher('Alice', 'Female', 'English')

print isinstance(t,Person)
print isinstance(t,Student)
print isinstance(t,Teacher)
print isinstance(t,object)

多态：这是动态语言和静态语言（例如Java）最大的差别之一。动态语言调用实例方法，不检查类型，只要方法存在，参数正确，就可以调用。

import json

class Students(object):
def read(self):
return r'["Tim","Bob","Alice"]'
s = Students()

print json.load(s)

多重继承：python支持多重继承，一个类可以有多个父类

class Person(object):
pass

class Student(Person):
pass

class Teacher(Person):
pass

class SkillMixin(object):
pass

class BasketballMixin(SkillMixin):
def skill(self):
return 'basketball'

class FootballMixin(SkillMixin):
def skill(self):
return 'football'

class BStudent(BasketballMixin,Student):
pass

class FTeacher(FootballMixin,Teacher):
pass

s = BStudent()
print s.skill()

t = FTeacher()
print t.skill()

获取对象信息：

isinstance（instance，class）

type（instance）获得对象类型

dir(instance)获得instance所有属性

getattr(instance,attr)获得instance指定属性值

setattr(instance,k,v)给instance绑定属性k 值为v