1.类与对象（构造方法与实例化）
#!/usr/bin/env python
# _*_ coding:UTF-8 _*_
class Province:
def __init__(self, name, capital, leader):
self.name = name
self.capital = capital
self.leader = leader
if __name__ == "__main__":
hebei = Province("河北", "石家庄", "刘道强")
print hebei.name
print hebei.capital
print hebei.leader
结果：
/Users/liudaoqiang/PycharmProjects/numpy/venv/bin/python /Users/liudaoqiang/Project/python_project/day05/day18/Province.py 河北 石家庄 刘道强 Process finished with exit code 0
注意：定义构造方法使用__init__方法
2.动态字段与静态字段
#!/usr/bin/env python
# _*_ coding:UTF-8 _*_
class Province:
memo = "中国的23个省之一"
def __init__(self, name, capital, leader):
self.name = name
self.capital = capital
self.leader = leader
if __name__ == "__main__":
hebei = Province("河北", "石家庄", "刘道强")
print hebei.name
print hebei.capital
print hebei.leader
print hebei.memo
print Province.memo
结果：
/Users/liudaoqiang/PycharmProjects/numpy/venv/bin/python /Users/liudaoqiang/Project/python_project/day05/day18/Province.py 河北 石家庄 刘道强 中国的23个省之一 中国的23个省之一 Process finished with exit code 0
注意：
（1）类不能访问动态字段
（2）对象可以访问静态字段
3.动态方法与静态方法
#!/usr/bin/env python
# _*_ coding:UTF-8 _*_
class Province:
memo = "中国的23个省之一"
def __init__(self, name, capital, leader):
self.name = name
self.capital = capital
self.leader = leader
def sports_meeting(self):
return self.name + "正在开运动会"
@staticmethod
def foo():
return "每个省都在反腐"
if __name__ == "__main__":
hebei = Province("河北", "石家庄", "刘道强")
print hebei.name
print hebei.capital
print hebei.leader
print hebei.memo
print Province.memo
print hebei.sports_meeting()
print hebei.foo()
print Province.foo()
结果：
/Users/liudaoqiang/PycharmProjects/numpy/venv/bin/python /Users/liudaoqiang/Project/python_project/day05/day18/Province.py 河北 石家庄 刘道强 中国的23个省之一 中国的23个省之一 河北正在开运动会 每个省都在反腐 每个省都在反腐 Process finished with exit code 0
注意：
（1）类不能访问动态方法
（2）对象可以方位静态方法
（3）在动态方法上增加@staticmethod并去除self参数则为动态方法
4.特性
#!/usr/bin/env python
# _*_ coding:UTF-8 _*_
class Province:
memo = "中国的23个省之一"
def __init__(self, name, capital, leader):
self.name = name
self.capital = capital
self.leader = leader
def sports_meeting(self):
return self.name + "正在开运动会"
@staticmethod
def foo():
return "每个省都在反腐"
@property
def bar(self):
return self.name
if __name__ == "__main__":
hebei = Province("河北", "石家庄", "刘道强")
print hebei.name
print hebei.capital
print hebei.leader
print hebei.memo
print Province.memo
print hebei.sports_meeting()
print hebei.foo()
print Province.foo()
print hebei.bar
结果：
/Users/liudaoqiang/PycharmProjects/numpy/venv/bin/python /Users/liudaoqiang/Project/python_project/day05/day18/Province.py 河北 石家庄 刘道强 中国的23个省之一 中国的23个省之一 河北正在开运动会 每个省都在反腐 每个省都在反腐 河北 Process finished with exit code 0
注意：
（1）在方法上增加@property则该方法变为字段访问
5.面向对象中动态方法与静态方法的比较
（1）使用动态方法适合于业务类；适用于对象数量较少的情况
（2）使用静态方法适合于工具类；适用于对象数量较多的情况，当对象较多则创建对象占用大量的内存这时应该使用静态方法
6.私有字段与私有方法
#!/usr/bin/env python
# _*_ coding:UTF-8 _*_
class Province:
memo = "中国的23个省之一"
def __init__(self, name, capital, leader, __thailand):
self.name = name
self.capital = capital
self.leader = leader
self.__thailand = __thailand
def sports_meeting(self):
return self.name + "正在开运动会"
@staticmethod
def foo():
return "每个省都在反腐"
@property
def bar(self):
return self.name
@property
def thailand(self):
return self.__thailand
if __name__ == "__main__":
hebei = Province("河北", "石家庄", "刘道强", True)
print hebei.name
print hebei.capital
print hebei.leader
print hebei.memo
print Province.memo
print hebei.sports_meeting()
print hebei.foo()
print Province.foo()
print hebei.bar
print hebei.thailand
结果：
/Users/liudaoqiang/PycharmProjects/numpy/venv/bin/python /Users/liudaoqiang/Project/python_project/day05/day18/Province.py 河北 石家庄 刘道强 中国的23个省之一 中国的23个省之一 河北正在开运动会 每个省都在反腐 每个省都在反腐 河北 True Process finished with exit code 0
注意：
（1）任何暴露给外部是无用的，或者为了安全不能暴露给外部的字段和方法需要设置为私有；设置私有字段和私有方法只需在前边加上两个下划线即可
（2）私有字段在类内部可以直接访问，在类外部不能访问，可以通过实现特性来访问私有字段
（3）私有方法在类内部可以直接访问，在类外部不能访问，可以通过封装共有方法来访问私有方法
7.只读特性与可写特性
#!/usr/bin/env python
# _*_ coding:UTF-8 _*_
class Province:
memo = "中国的23个省之一"
def __init__(self, name, capital, leader, __thailand):
self.name = name
self.capital = capital
self.leader = leader
self.__thailand = __thailand
def sports_meeting(self):
return self.name + "正在开运动会"
@staticmethod
def foo():
return "每个省都在反腐"
@property
def bar(self):
return self.name
@property
def thailand(self):
return self.__thailand
@thailand.setter
def thailand(self, __thailand):
self.__thailand = __thailand
if __name__ == "__main__":
hebei = Province("河北", "石家庄", "刘道强", True)
print hebei.name
print hebei.capital
print hebei.leader
print hebei.memo
print Province.memo
print hebei.sports_meeting()
print hebei.foo()
print Province.foo()
print hebei.bar
print hebei.thailand
hebei.thailand = False
print hebei.thailand
结果：
/Users/liudaoqiang/PycharmProjects/numpy/venv/bin/python /Users/liudaoqiang/Project/python_project/day05/day18/Province.py 河北 石家庄 刘道强 中国的23个省之一 中国的23个省之一 河北正在开运动会 每个省都在反腐 每个省都在反腐 河北 True False Process finished with exit code 0
/Users/liudaoqiang/PycharmProjects/numpy/venv/bin/python /Users/liudaoqiang/Project/python_project/day05/day18/Province.py 河北 石家庄 刘道强 中国的23个省之一 中国的23个省之一 河北正在开运动会 每个省都在反腐 每个省都在反腐 河北 True False Process finished with exit code 0
注意
（1）使用@property装饰器则私有字段可读；使用@field.setter则私有字段可写
8.构造方法__init__()，析构方法__del__()和__call__()
#!/usr/bin/env python
# _*_ coding:UTF-8 _*_
class Province:
memo = "中国的23个省之一"
def __init__(self, name, capital, leader, __thailand):
self.name = name
self.capital = capital
self.leader = leader
self.__thailand = __thailand
def __call__(self, *args, **kwargs):
print "CALL"
def __del__(self):
print "DELETE"
def sports_meeting(self):
return self.name + "正在开运动会"
@staticmethod
def foo():
return "每个省都在反腐"
@property
def bar(self):
return self.name
@property
def thailand(self):
return self.__thailand
@thailand.setter
def thailand(self, __thailand):
self.__thailand = __thailand
if __name__ == "__main__":
hebei = Province("河北", "石家庄", "刘道强", True)
print hebei.name
print hebei.capital
print hebei.leader
print hebei.memo
print Province.memo
print hebei.sports_meeting()
print hebei.foo()
print Province.foo()
print hebei.bar
print hebei.thailand
hebei.thailand = False
print hebei.thailand
hebei()
结果：
/Users/liudaoqiang/PycharmProjects/numpy/venv/bin/python /Users/liudaoqiang/Project/python_project/day05/day18/Province.py 河北 石家庄 刘道强 中国的23个省之一 中国的23个省之一 河北正在开运动会 每个省都在反腐 每个省都在反腐 河北 True False CALL DELETE Process finished with exit code 0
注意：
__init__(self)在创建对象的时候触发调用
__del__(self)在销毁对象的时候触发调用
__call__(self)在对象()调用时触发调用
9.类的继承
#!/usr/bin/env python
# _*_ coding:UTF-8 _*_
class Base:
def __int__(self):
pass
def __call__(self, *args, **kwargs):
pass
def __del__(self):
pass
def foo(self):
print "foo"
def bar(self):
print "bar"
class Derive(Base):
def __int__(self):
pass
def __call__(self, *args, **kwargs):
pass
def __del__(self):
pass
def bar(self):
Base.bar(self)
print "derive"
if __name__ == "__main__":
base = Base()
base.foo()
base.bar()
derive = Derive()
derive.foo()
derive.bar()
结果：
/Users/liudaoqiang/PycharmProjects/numpy/venv/bin/python /Users/liudaoqiang/Project/python_project/day05/day18/extend_test.py foo bar foo bar derive Process finished with exit code 0
注意：
（1）继承只需要的类名的后面加上基类的名称
（2）调用基类的方法则用Base.bar(self)
10. 多继承
经典类的深度优先多继承：
#!/usr/bin/env python
# _*_ coding:UTF-8 _*_
class A:
def __init__(self):
print "init A"
def save(self):
print "save from A"
class B(A):
def __init__(self):
print "init B"
class C(A):
def __init__(self):
print "init C"
def save(self):
print "save from C"
class D(B, C):
def __init__(self):
print "init D"
if __name__ == "__main__":
d = D()
d.save()
结果：
/Users/liudaoqiang/PycharmProjects/numpy/venv/bin/python /Users/liudaoqiang/Project/python_project/day05/day18/object_test.py init D save from A Process finished with exit code 0
新式类的广度优先多继承：
#!/usr/bin/env python
# _*_ coding:UTF-8 _*_
class A(object):
def __init__(self):
print "init A"
def save(self):
print "save from A"
class B(A):
def __init__(self):
print "init B"
class C(A):
def __init__(self):
print "init C"
def save(self):
print "save from C"
class D(B, C):
def __init__(self):
print "init D"
if __name__ == "__main__":
d = D()
d.save()
结果：
/Users/liudaoqiang/PycharmProjects/numpy/venv/bin/python /Users/liudaoqiang/Project/python_project/day05/day18/object_test.py init D save from C Process finished with exit code 0
注意：
（1）python中的类如果不继承object则为经典类，如果继承object类则为新式类
（2）经典类的多继承采用深度优先算法继承，新式类的多继承采用广度优先算法继承
11.接口，抽象类，抽象方法
例如：
#!/usr/bin/env python
# _*_ coding:UTF-8 _*_
from abc import ABCMeta, abstractmethod
class Foo:
__metaclass__ = ABCMeta
def save(self):
pass
class Bar(Foo):
def __init__(self):
print "init Bar"
def save(self):
print "save from Bar"
if __name__ == "__main__":
bar = Bar()
bar.save()
结果：
/Users/liudaoqiang/PycharmProjects/numpy/venv/bin/python /Users/liudaoqiang/Project/python_project/day05/day18/abstract_test.py init Bar save from Bar Process finished with exit code 0
注意：
（1）抽象类中只有抽象方法即为借口
（2）类中有__metaclass__ = ABCMeta的类即为抽象类；方法被@abstractmethod装饰即为抽象方法