反射(hasattr,getattr,setattr,delattr)

目录

• 反射
• 反射的应用

反射

• 反射就是通过字符串来操作类或者对象的属性

• 反射本质就是在使用内置函数，其中反射有以下四个内置函数：
  1. hasattr
  2. getattr
  3. setattr
  4. delattr

class People:
    country = 'China'

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

    def eat(self):
        print('%s is eating' % self.name)


peo1 = People('egon')

print(hasattr(peo1, 'eat'))  # peo1.eat

True

print(getattr(peo1, 'eat'))  # peo1.eat

<bound method People.eat of <__main__.People object at 0x104e25cf8>>

print(getattr(peo1, 'xxxxx', None))

None

setattr(peo1, 'age', 18)  # peo1.age=18
print(peo1.age)

18

print(peo1.__dict__)

{'name': 'egon', 'age': 18}

delattr(peo1, 'name')  # del peo1.name
print(peo1.__dict__)

{'age': 18}

反射的应用

class Ftp:
    def __init__(self, ip, port):
        self.ip = ip
        self.port = port

    def get(self):
        print('GET function')

    def put(self):
        print('PUT function')

    def run(self):
        while True:
            choice = input('>>>: ').strip()

            if choice == 'q':
                print('break')
                break

#             print(choice, type(choice))
#             if hasattr(self, choice):
#                 method = getattr(self, choice)
#                 method()
#             else:
#                 print('输入的命令不存在')

            method = getattr(self, choice, None)

            if method is None:
                print('输入的命令不存在')
            else:
                method()

conn = Ftp('1.1.1.1', 23)
conn.run()

>>>: get
GET function
>>>: put
PUT function
>>>: q
break