**super**
super遵循的是mro算法
只在新式类中能使用
py2新式类中需要自己添加参数（子类名，子类对象）
**封装**
1.广义上的封装
2.狭义上的封装: __名字
方法名私有化
实例变量私有化
静态变量私有化
私有化的特点：
只能在类的内部使用
私有的各种静态变量和方法不能继承
不能被子类继承
**内置函数**
判断一个变量是否可调用
callable(名字）
装饰器
@prooerty把一个方法伪装成属性
给伪装成属性的方法赋值 @函数名.setter装饰器
**反射相关**
hasattr()
getattr()
字符串数据类型的变量，采用getattr(对象，‘变量名’)获取变量的值
class File:
lst = [('读文件','read'), ('写文件','write'),
('删除文件','remove'), ('文件重命名','rename')
,('复制','copy')]
def __init__(self,filepath):
self.filepath = filepath
def write(self):
print('in write')
def read(self):
print('in read')
def remove(self):
print('in remove')
def rename(self):
print('in rename')
def copy(self):
print('in copy')
f = File('ss')
lst = ['读文件','写文件','删除文件','文件重命名','复制']
for index,opt in enumerate(File.lst,1):
print(index,opt[0])
num = int(input('请输入你要选择的序号>>>'))
if hasattr(f,File.lst[num-1][1]):
getattr(f,File.lst[num-1][1])()
'''
classmethod
1.定义一个方法，默认传self，但这个self没被使用
2.在这个方法利用到了当前的类名，或者准备使用这个类的内存空间的名字的时候
把一个对象绑定的方法修改成一个类方法：在方法中仍然可以引用类中的静态变量，可以不用实例化对象，直接用类名在外部调用这个方法
'''
class Goods:
__discount = 0.8
def __init__(self):
self.__price = 5
self.price = self.__price*self.__discount
@classmethod
def change_discount(cls,new_discount):
cls.__discount = new_discount
print(cls.__discount)
Goods.change_discount(0.6)
apple = Goods()
print(apple.price)
import time
class Data:
def __init__(self,year,month,day):
self.year = year
self.month = month
self.day = day
@classmethod
def today(cls):
struct_t = time.localtime()
data = cls(struct_t.tm_year,struct_t.tm_mon,struct_t.tm_mday)
return data
tody = Data.today()
print(tody.year)
print(tody.day)
print(tody.month)
```python
'''
staticmethod
'''
class User:
@staticmethod
def login(a,b):
print('登录',a,b)
User.login(1,2)
obj = User()
obj.login(3,4)
class A:
country = 'China'
def func(self):
print(self.__dict__)
@classmethod
def clas_func(cls):
print(cls)
@staticmethod
def stat_func():
print('普通函数')
@property
def name(self):
return 'wahaha'
a = A()
a.country='123'
print(a.country)
print(A.country)
结果
123
China
class A:
pass
obj = A()
print(callable(obj))
结果：
FALSE
class B:
def __call__(self, *args, **kwargs):
print('helo!oleh')
obj1 = B()
print(callable(obj1))
obj1()
结果：
True
helo!oleh
class Cls:
def __init__(self,name):
self.name = name
self.student = []
def __len__(self):
return len(self.student)
qq = Cls('helo')
qq.student.append('HELO!')
qq.student.append('HELO!1')
qq.student.append('HELO!2')
qq.student.append('HELO!3')
print(len(qq.student))
print(qq.__len__())
print(len(qq))
结果：
4
4
4
class A:
def __new__(cls, *args, **kwargs):
o = super().__new__(cls)
print('执行new',o)
return o
def __init__(self):
print('执行init',self)
A()
class B:
__instance = None
def __new__(cls, *args, **kwargs):
if cls.__instance is None:
cls.__instance = super().__new__(cls)
return cls.__instance
def __init__(self,cloth,pants):
self.cloth = cloth
self.pants = pants
b1 = B('红毛衣','绿皮裤')
b2 = B('红毛衣','黑豹文')
print(b1)
print(b1.pants)
print(b2)
print(b2.pants)
结果：
<__main__.B object at 0x7f4a550ae9a0>
黑豹文
<__main__.B object at 0x7f4a550ae9a0>
黑豹文
python的模块单例模式
单例.py
class Baby:
def __init__(self,cloth,pants):
self.cloth = cloth
self.pants = pants
baby = Baby('红上衣','鹿皮裤')
调用单例模式.py
from 单例 import baby
print(baby)
print(baby)
print(baby)
结果：
<单例.Baby object at 0x7fdd3416e8b0>
<单例.Baby object at 0x7fdd3416e8b0>
<单例.Baby object at 0x7fdd3416e8b0>
class Course:
def __init__(self,name,price,period):
self.name = name
self.price = price
self.period = period
def __str__(self):
return 'aaaaaaaa'
python = Course('python',21800,'6 months')
linux = Course('linux',19800,'5 months')
mysql = Course('mysql',12800,'3 months')
go = Course('go',15800,'4 months')
print(go)
结果：
aaaaaaaa
class Course:
def __init__(self,name,price,period):
self.name = name
self.price = price
self.period = period
def __str__(self):
return ','.join([self.name,str(self.price),self.period])
python = Course('python',21800,'6 months')
linux = Course('linux',19800,'5 months')
mysql = Course('mysql',12800,'3 months')
go = Course('go',15800,'4 months')
print(go)
print(str(go))
print('这是%s' %(go))
结果：
go,15800,4 months
go,15800,4 months
这是go,15800,4 months
Processed:
0.014, SQL:
9
