class Info:

     def __init__(self,name,age,gender):

         self.name = name

         self.age  = age

         self.gender = gender

     def show(self):

         return '%s - %s' %(self.name,self.age)

obj = Info('alex','20','男')

b = 'name'

print(obj.__dict__[b])

print(obj.__dict__['name'])

#getattr()

inp = input('请输入想要获取的内容：')

v = getattr(obj,inp)

print(v)

func = getattr(obj,'show')

v = func()

print(v)

#hasattr()

print(hasattr(obj,'name'))

#setattr()

setattr(obj,'k1','v1')

#delattr(obj,'gender')

obj.gender  # 此时报错，Info类中的gender对象已被删除

class Info(object):

    staticField = "Hello World!"

    def __init__(self):

        self.name = 'mike'

    def func(self):

        return 'func'

    @staticmethod

    def bar():

        return 'bar'

print(getattr(Info, 'staticField'))

print(getattr(Info, 'func'))   # 返回函数的内存地址

print(getattr(Info, 'bar'))    # 返回函数的内存地址

class Info:

    __v = None

    @classmethod

    def get_instance(cls):

        if cls.__v:

            return cls.__v

        else:

            cls.__v = Info()

            return cls.__v

obj1 = Info.get_instance()

print(obj1)

obj2 = Info.get_instance()

print(obj2)