os.system 输出命令结果到屏幕，返回命令执行状态
os.popen（"dir"）.read()#会保存命令的执行结果输出
py2.7
commands
commands.getstatusoutput("dir")
#windows不好用
#linux可以
subprocess
==================================
面向对象
模板造对象
一.类的特性
1.封装
防止数据被随意修改
使外部程序不需要关注对象内部的构造（逻辑结构)，只需要通过此对象对外提供的接口进行直接访问即可
1 class Dog(object):
2
3 def __init__(self,name,food):#构造函数，构造方法，==初始化方法
4 self.NAME = name
5 self.FOOD = food
6 self.__getj = 'big'
7 self.__test = '123'
8 def sayhi(self):#类的方法（类的具体方法）
9 print("hello,ni shuo de dui.",self.NAME)
10 def get_getj(self):
11 return self.__getj
12 def eat(self):
13 print("%s is eating %s"%(self.NAME,self.FOOD))
14 def __del__(self):
15 print("del...run....")
16
17
18 d = Dog("a1",'haochide')#Dog(d,"a1") #实例化后产生的对象叫实例（当前类的实例）
19 d2 = Dog("a2",'pi')
20
21 d.sayhi()
22 d2.sayhi()
23 d.eat()
24 d2.eat()
25 print(d.get_getj())
26
27 print(d._Dog__test)
28
29 def shot2():
30 print("buhuia")
31
32 d.sayhi = shot2
33 d.sayhi()
34 # print(d.test)
2.继承
通过父类---》子类的方式 实现不同角色的共同点和不同点 以最小代码量的方式实现
类 ----》实例化----》实例对象
__init__构造函数
self.name = name #属性，成员变量，字段
def sayhi（） #方法，动态属性
公有属性
在类里定义的属性，任何对象都可以访问
私有属性
__private_attr_name = value
def get_heart(self) #对外部提供只读访问接口
return self.__heart
r1._Role__heart 强制访问私有属性
析构方法
继承
多继承
1 class Person(object):
2 def __init__(self,name,age):
3 self.name = name
4 self.age = age
5 self.sex = 'male'
6
7 def talk(self):
8 print("person is talk",self.name)
9
10
11 class BlackPerson(Person):
12 def __init__(self,name,age):
13 Person.__init__(self,name,age)
14 print(self.sex)
15
16 def walk(self):
17 print("is walk")
18
19
20
21 b = BlackPerson('liusijia',10)
22 b.talk()
新式类vs经典类
SchoolMember.__init__(self,name,age,sex) #经典类写法
super(Teacher,self).__init__(name,age,sex)#新式类写法
class Person(object):
super(Person)
class Person:#经典类
ParentClass.__init__
1 class SchoolMember(object):
2 '''学校成员基类'''
3 member = 0
4 def __init__(self,name,age,sex):
5 self.name = name
6 self.age = age
7 self.sex = sex
8 self.enroll()
9 def enroll(self):
10 '''注册'''
11 print("just encolled a new school member %s"%self.name)
12 SchoolMember.member +=1
13
14 def tell(self):
15 '''个人信息'''
16 print('------info:%s-----'%self.name)
17 for k,v in self.__dict__.items():
18 print('\t',k,v)
19 def __del__(self):
20 print("开除[%s]..."%self.name)
21 SchoolMember.member -=1
22
23 class School(object):
24 '''学校类'''
25 def open_branch(self,addr):
26 print("openning branch in %s"%addr)
27 self.addr = ""
28
29 class Teacher(SchoolMember,School):
30 '''讲师类'''
31 def __init__(self,name,age,sex,salary,course):
32 SchoolMember.__init__(self,name,age,sex) #经典类写法
33 super(Teacher,self).__init__(name,age,sex)#新式类写法
34
35 self.salary = salary
36 self.course = course
37 # self.enroll()
38
39 def teaching(self):
40 print("Teacher[%s]is teaching[%s]"%(self.name,self.course))
41
42 class Student(SchoolMember):
43 def __init__(self,name,age,sex,course,tuition):
44 SchoolMember.__init__(self,name,age,sex)
45 self.course = course
46 self.tuition = tuition
47 self.amount = 0
48
49 def pay_tuition(self,amount):
50 print("student[%s]has just paied [%s]"%(self.name,amount))
51 self.amount += amount
52
53 t1 = Teacher("a1",11,"F*M",3000,"python")
54 s1 = Student("a2",14,"NA","py",3000)
55 s2 = Student("a3",13,"NA","py",3000)
56
57 print(SchoolMember.member)
58
59
60 del s1
61 print(SchoolMember.member)
62
63 t1.tell()
64 s2.tell()
3.多态
静态方法
类方法
属性方法
