python内部类
内部类的实例化方法
- 直接使用外部类调用内部类
object_name = outclass_name.inclass_name()
- 先对外部类进行实例化，在实例化内部类
out_name = outclass_name()
in_name = out_name.inclass_name()
in_name.method()
类的内置方法
-
__str__() : 给类设置返回值
#!/usr/bin/python
#coding:utf8
class MyClass(object):
name = 'Karl'
id = 007
__age = 18
def think(self):
self.__age = 28
name = 'John'
print "My name is %s" %self.name
print "My age is %s" %self.__age
def __secret(self):
print "I can tell you a secret!"
def tell(self):
self.__secret()
def __str__(self):
return "This is MyClass" # 只能用return，不能用print
@staticmethod
def test(): # 注意没带参数self
print "This is a static func"
@classmethod
def test2(self):
print "This is a class func"
# cm = classmethod(test2) # 类方法
# sm = staticmethod(test) # 静态方法
me = MyClass()
print me
[root@KARL ~]# python u3.py
This is MyClass
# 若没有__str__()方法，则打印如下
[root@KARL ~]# python u3.py
<__main__.MyClass object at 0x7f25c440fcd0>
-
__init__() : 构造函数(可选)，用于初始化类的内部状态
-
__del__() : 析构函数(可选)，用于释放对象占用的资源
1 #!/usr/bin/python
2 #coding:utf8
3
4 class MyClass(object):
5 name = 'Karl'
6 id = 007
7 __age = 18
8
9
10 def tell(self):
11 self.__secret()
12
13 def __str__(self):
14 return "This is MyClass" # 只能用return，不能用print
15
16 def __init__(self):
17 self.name = "Default"
18 print "Init ..."
19 print "The name is %s" %self.name
20
21 def __del__(self):
22 print "Del ..."
23
24
25 @staticmethod
26 def test(): # 注意没带参数self
27 print "This is a static func"
28
29 @classmethod
30 def test2(self):
31 print "This is a class func"
32
33 me = MyClass() # 仅仅实例化类
[root@KARL ~]# python u3.py
Init ...
The name is Default
Del ...
类的继承
- 子类继承类父类的所有公有属性和方法
- 继承实现类代码复用
- class MyClass(ParentClass1 [, ParentClass2, ...])
- 若父类定义了
__init__()方法，子类必须显示调用父类的__init__()方法
- 若子类需要扩展父类的行为，可添加
__init__()方法的参数
- 子类调用父类的构造函数有以下2种方式
ParentClass.__init__(self [, args ...])super(MyClass, self).__init__([args ...])
#!/usr/bin/python
#coding:utf8
class MyClass(object):
name = 'Karl'
id = 007
__age = 18
def __str__(self):
return "This is MyClass" # 只能用return，不能用print
def __init__(self, c):
self.name = "Default"
print "Init ..."
print "The name is %s" %self.name
print "I am %s" %c
def __del__(self):
print "Del ..."
@staticmethod
def test(): # 注意没带参数self
print "This is a static func"
@classmethod
def test2(self):
print "This is a class func"
class SonClass(MyClass):
def __init__(self):
# MyClass.__init__(self, 'black')
super(SonClass, self).__init__('black') # 父类名后必须带有(object)时，才能使用super，注意super的参数用子类名
me = SonClass() # 仅仅实例化类
[root@KARL ~]# vim u3.py
[root@KARL ~]# python u3.py
Init ...
The name is Default
I am black
Del ...
多重继承
- 多重继承时，若多个父类定义了
__init__()方法时，子类只执行第一个类的__init__()方法
