Python面试题之Python对象反射、类反射、模块反射（python 反射）

Python面试题之Python对象反射、类反射、模块反射（python 反射）

python面向对象中的反射：通过字符串的形式操作对象相关的属性。python中的一切事物都是对象（都可以使用反射）

一、getattr

对象获取

class Manager: role = "管理员" def __init__(self,name,sex,phone,mail): self.name = name self.sex = sex self.phone = phone self.mail = mail def createClass(self): print("create class") def createTeacher(self): print("createTeacher") def createStu(): print("createStu")manager = Manager("safly","男",123456,123456)print("---对象获取对象方法-----")f = getattr(manager,"createClass")f()print("---对象获取对象属性-----")name = getattr(manager,"name")print(name)print("---对象获取类属性-----")role = getattr(manager,"role")print(role)print("---对象获取类属性(可以设置默认值)-----")import loggingif hasattr(manager,"role1"): role = getattr(manager,"role1","roleDefault") print(role)else: logging.warn("没有role属性") role = getattr(manager, "role1", "roleDefault") print(role)

类获取

class Manager: role = "管理员" def createClass(self): print("create class") def createStu(): print("createStu")m = Manager()f = getattr(Manager,"createClass")f(Manager)f = getattr(Manager,"createClass")f(m)role = getattr(Manager,"createStu")role()#对象获取类属性role = getattr(Manager,"role")print(role)

输出如下：

create classcreate classcreateStu管理员

二、setattr

设置类属性、方法

class Manager: role = "管理员" def __init__(self,name,sex,phone,mail): self.name = name self.sex = sex self.phone = phone self.mail = mail def createClass(self): print("create class") def createTeacher(self): print("createTeacher") def createStu(): print("createStu")manager = Manager("safly","男",123456,123456)print("----设置类属性------")setattr(Manager,"country","china")print(Manager.country)print("----删除类属性------")delattr(Manager,"country")# #删除报错# print(Manager.country)print("----设置类方法------")def Method(parm): print("我是被绑定的class之外的方法parm--",parm)setattr(Manager,"Method",Method)Manager.Method("saf")Manager.Method(Manager)Manager.Method(manager)def Method(): print("我是被绑定的class之外的方法parm--")setattr(Manager,"Method",Method)Manager.Method()

输出如下：

E:\python\python_sdk\python.exe E:/python/py_pro/demo.py----设置类属性------china----删除类属性----------设置类方法------我是被绑定的class之外的方法parm-- saf我是被绑定的class之外的方法parm-- 我是被绑定的class之外的方法parm-- <__main__.Manager object at 0x0343B4B0>我是被绑定的class之外的方法parm--Process finished with exit code 0

设置对象属性、方法

class Manager: role = "管理员" def __init__(self,name,sex,phone,mail): self.name = name self.sex = sex self.phone = phone self.mail = mail def createClass(self): print("create class") def createTeacher(self): print("createTeacher") def createStu(): print("createStu")manager = Manager("safly","男",123456,123456)print("----设置对象属性------")setattr(manager,"age",20)print(manager.age)print("----删除对象属性------")delattr(manager,"age")# 'Manager' object has no attribute 'age'# print(manager.age)print("---对象不能删除类属性---")setattr(Manager,"country","china")print(Manager.country)# delattr(manager,"country")# print(Manager.country)print("----设置对象方法------")def create_course(self): print('创建了一个课程')setattr(manager,'create_course',create_course)manager.create_course(manager)def create_grade(): print('创建了一个班级')setattr(manager,'create_grade',create_grade)manager.create_grade()

输出如下：

E:\python\python_sdk\python.exe E:/python/py_pro/demo.py----设置对象属性------20----删除对象属性---------对象不能删除类属性---china----设置对象方法------创建了一个课程创建了一个班级Process finished with exit code 0

三、模块反射

创建一个模块mokuai.py

a = 1def method(rag): print(rag) return "666"

然后在python.py中导入以上模块

import mokuaiprint(getattr(mokuai,"a"))method = getattr(mokuai,"method")ret = method(8888)print(ret)

输出如下：

18888666

四、反射本模块函数、变量

aa = 11def method(): print("---method---")import sysprint(sys.modules[__name__])print(getattr(sys.modules[__name__],"aa"))f = getattr(sys.modules[__name__],"method")f()

输出如下：

E:\python\python_sdk\python.exe E:/python/py_pro/demo.py11---method---Process finished with exit code 0

​​参考​​

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