day22

eval 模块转换dict, list, tuple

dict = {'name':'gg', 'age':18}
lists = [1,2,3,4,5,6,[7,8]]
tuples = (1,2,3,4,5,'a','c')

print(eval(str(dict)))
print(eval(str(lists)))
print(eval(str(tuples)))

json

loads and down

静态方法 @property

class tests:
    def __init__(self, x, y):
        self.x = x
        self.y = y
    @property
    def sum(self):
        print('x*y = %s' %(self.x+self.y))

test = tests(5,8)
print(test.x)
print(test.y)
test.sum

输出结果：
5
8
x*y = 13

@类方法 @classmethod

class tests:
    tag = 1
    def __init__(self, x, y):
        self.x = x
        self.y = y
    @property
    def sum(self):
        print('x*y = %s' %(self.x+self.y))
    @classmethod
    def ggg(cls): 
        print(cls)
        print('==',cls.tag)
test = tests(5,8)
print(test.x)
test.sum
print("*************************")
tests.ggg()

输出结果：
5
x*y = 13
*************************
<class '__main__.tests'>
== 1

静态属性

class tests:
    tag = 1
    def __init__(self, x, y):
        self.x = x
        self.y = y
    @property
    def sum(self):
        print('x*y = %s' %(self.x+self.y))
    @classmethod
    def ggg(cls,z): //类方法传参
        print(cls)
        print('==',cls.tag, z)
    @staticmethod
    def xxx(a,b):
        print(a,b)
test = tests(5,8)
print(test.x)
test.sum
print("*************************")
tests.ggg(22)
print("*************************")
tests.xxx(2,3)

输出结果：
5
x*y = 13
*************************
<class '__main__.tests'>
== 1 22
*************************
2 3

组合，先实例化 Teacher，再把实例化的 t 传入实例化 School 中，实现组合

class School:
    def __init__(self, local, teacher_name):
        self.local = local
        self.teacher_name = teacher_name

class Teacher:
    def __init__(self, name):
        self.name = name

t = Teacher('gg')  //将实例化的 t 传入 s 中
s = School('Beijing', t)

print(t.__dict__)
print(s.__dict__)
print(s.teacher_name.name)

输出结果：
{'name': 'gg'}
{'local': 'Beijing', 'teacher_name': <__main__.Teacher object at x000001C089ECAB38>}
gg

继承，子类继承父类

class man:
    def __init__(self, name, gender):
        self.name = name
        self.gender =  gender
    def head(self):
        print('this is head')
    def others(self):
        print('this is others')

class student(man): #继承父类
    # 子类可以再定义，定义重复会使用子类方法，如 init
    def __init__(self, id, name, gender):
        self.id = id
        self.name = name
        self.gender = gender

s = student('16040', 'libai', 'none')
print(s.__dict__)
s.head()

输出结果：
{'id': '16040', 'name': 'libai', 'gender': 'none'}
this is head

接口继承，在子类中必须定义某些方法，如 others

import abc
class man(metaclass=abc.ABCMeta):
    def __init__(self, name, gender):
        self.name = name
        self.gender =  gender
    def head(self):
        print('this is head')
    @abc.abstractmethod #要求必须在子类中定义others方法，没定义不能实例化
    def others(self):
        print('this is others')

class student(man): #继承父类
    # 子类可以再定义，定义重复会使用子类方法
    def __init__(self, id, name, gender):
        self.id = id
        self.name = name
        self.gender = gender
    def others(self):  #必须定义others
        print('son others')
        
s = student('16040', 'libai', 'none')
print(s.__dict__)
s.others()

输出结果：
{'id': '16040', 'name': 'libai', 'gender': 'none'}
son others

继承顺序，深度优先与广度优先，python3 都是新式类，python2 分为新式类和经典类

可以看：https://blog.csdn.net/oxiaoxio/article/details/50463484

子类调用父类方法

class man():
    def __init__(self, name, gender):
        self.name = name
        self.gender =  gender
    def head(self):
        print('this is head')

    def others(self):
        print('this is others')

class student(man):
    def __init__(self, id, name, gender):
        man.__init__(self, name, gender) #子类使用父类方法，必须传入self
        self.id = id
    def others(self):
        man.others(self) #使用父类方法
        print('son others')

s = student('16040', 'libai', 'none')
print(s.__dict__)
s.others()

输出结果：
{'name': 'libai', 'gender': 'none', 'id': '16040'}
this is others
son others

用 super 调用父类方法

class man():
    def __init__(self, name, gender):
        self.name = name
        self.gender =  gender
    def others(self):
        print('this is others')

class student(man):
    def __init__(self, id, name, gender):
        super().__init__(name, gender) #用super调用父类方法
        # 类似于 super(student, self).__init__(name, gender)
        self.id = id
    def others(self):
        super().others() #super
        print('son others')

s = student('16040', 'libai', 'none')
print(s.__dict__)
s.others()

输出结果：
{'name': 'libai', 'gender': 'none', 'id': '16040'}
this is others
son others