面向对象——反射及动态导入（三十二）

反射：主要指程序可以访问，检测和修改它本身状态或行为的一种能力（自省）

四个可以实现自省的函数

一下方法适用于类和对象

hasattr(object, name)
判断object中有没有一个name字符串对应的方法和属性

getattr(object, name, default=None)
setattr(x, y, v)
delattr(x, y)

class People:
    __star = "earth"
    def __init__(self,name,id,sex):
        self.Name = name
        self.Id = id
        self.Sex = sex

    def get_star(self):
        print("%s" %(self.__star))

p1 = People("zhangsan",123456,"male")
p1.get_star()

print(hasattr(p1,"Name")) # True
print(hasattr(p1,"get_star")) # True

print(getattr(p1,"Id")) # 123456
print(getattr(p1,"abcd", "没有这个参数")) # 没有这个参数
print(getattr(p1,"get_star")) #
'''
<bound method People.get_star of <__main__.People object at 0x000001E3D1448940>>
'''
fun = getattr(p1,"get_star")
fun()

print(p1.__dict__) # {'Name': 'zhangsan', 'Id': 123456, 'Sex': 'male'}
setattr(p1,"Height",180)
setattr(p1,"func",lambda x:x+1)
print(p1.__dict__) # {'Height': 180, 'Name': 'zhangsan', 'func': <function <lambda> at 0x000002603DB67B70>,
                    # 'Sex': 'male', 'Id': 123456}
print(p1.func(2))

delattr(p1,"Sex")
print(p1.__dict__) # {'Height': 180, 'Id': 123456, 'Name': 'zhangsan'}

if hasattr(p1,"Sex"):
    print("%s" %p1.Sex)
else:
    print("do something...")

动态导入

module_t = __import__("m1.test1") # 传入字符串
print(module_t)
module_t.test1.test2()
'''
<module 'm1' from 'E:\06_python\python_demo\test3\OO\m1\__init__.py'>
test2...
'''

# m1/test1
def test1():
    print("test1...")

def test2():
    print("test2...")

注意

# m1/test1
def test1():
    print("test1...")

def _test2(): # _ 声明为私有
    print("test2...")

from m1.test1 import * # 导入所有

test1._test2() # 报错

 

module_t = __import__("m1.test1") # 传入字符串
print(module_t) # <module 'm1' from 'E:\06_python\python_demo\test3\OO\m1\__init__.py'>
module_t.test1.test1()  # test1...

import importlib
m = importlib.import_module("m1.test1")
print(m) # <module 'm1.test1' from 'E:\06_python\python_demo\test3\OO\m1\test1.py'>
m.test1() # test1...