反射机制

反射：通过字符串的形式去模块，对象中找寻指定的函数（方法）并执行。

hasattr

class Person(object):
    def talk(self):
        print('skr')

p = Person()
print(hasattr(p, 'talk'))
print(hasattr(p, 'say_hello'))

# True
# False

getattr

class Person(object):
    def talk(self):
        print('skr')

p = Person()
func = getattr(p, 'talk')
print(func)
func()

# <bound method Person.talk of <__main__.Person object at 0x0000000002A73358>>
# skr

setattr

def say_hello(self):
    print('hello!')

class Person(object):
    def talk(self):
        print('skr')

p = Person()
setattr(p, 'say_hello', say_hello)
p.say_hello(p)
# hello!

delattr

class Person(object):
    def talk(self):
        print('skr')

p = Person()
delattr(p, 'talk')
p.talk()

Traceback (most recent call last):
  File "oop.py", line 8, in <module>
    delattr(p, 'talk')
AttributeError: 'Person' object attribute 'talk' is read-only

p = Person()
setattr(p, 'hehe', 111)
p.hehe
delattr(p, 'hehe')
p.hehe

Traceback (most recent call last):
  File "oop.py", line 12, in <module>
    p.hehe
AttributeError: 'Person' object has no attribute 'hehe'