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 = leaderif __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 = leaderif __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.nameif __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.__thailandif __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TrueProcess 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 = __thailandif __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TrueFalseProcess 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TrueFalseProcess 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 = __thailandif __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TrueFalseCALLDELETEProcess 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.pyfoobarfoobarderiveProcess 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.pyinit Dsave from AProcess 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.pyinit Dsave from CProcess 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, abstractmethodclass Foo: __metaclass__ = ABCMeta def save(self): passclass 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.pyinit Barsave from BarProcess 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
