python 入坑路 反射

一、概述

　　反射我们以后会经常用到，这个东西实现了动态的装配，通过字符串来反射类中的属性和方法

二、反射函数

2.1 hasattr(obj,name_str)

作用：判断一个对象 obj,是否有用户输入的方法及属性 ，有就返回True , 没有就False

class Dog(object):
    '''
    dog class
    '''
    class_shuxing="hehe"
    def __init__(self,name):
        self.name=name
        self.age=None
        self.__sex=None

    def walk(self):
        print("%s is walking..." %self.name)


    def eat(self,food):
        print("%s is eating %s" %(self.name,food))

    def age(self,age):
        self.age=age

    def sex(self):
        return self.__sex

str=input("pls input:").strip()
print(hasattr(Dog,str))

---- 
输入：eat  True
输入;name  False

　　2.2 getattr(obj,str)

作用：根据 用户输入 str 去获取一个obj 方法的内存地址，

class Dog(object):
    '''
    dog class
    '''
    class_shuxing="hehe"
    def __init__(self,name):
        self.name=name
        self.age=None
        self.__sex=None

    def walk(self):
        print("%s is walking..." %self.name)


    def eat(self,food):
        print("%s is eating %s" %(self.name,food))

    def age(self,age):
        self.age=age

    def sex(self):
        return self.__sex
str=input("pls input:").strip()
print(getattr(Dog,str))
---
pls input:eat
<function Dog.eat at 0x0000000002339158>

　　2.3 setattr  

作用：把一个函数，动态的传到一个类中， 相当于 静态方法，结合前面两个以前用，show tiem...

class Dog(object):
    '''
    dog class
    '''
    class_shuxing="hehe"
    def __init__(self,name):
        self.name=name
        self.age=None
        self.__sex=None

    def walk(self):
        print("%s is walking..." %self.name)


    def eat(self,food):
        print("%s is eating %s" %(self.name,food))

    def age(self,age):
        self.age=age

    def sex(self):
        return self.__sex

def bulk(self):
    print("%s is bulking..." %self.name)

d=Dog("NIUBI")
str=input("pls input:").strip()
if hasattr(d,str):
    getattr(d,str)()
else:
    setattr(d,str,bulk)#调用的名称是输入的str ,相当于给 bulk 函数改名字，传入Dog 类
    getattr(d,str)(d) #需要把 obj 传进去

　　2.4 delattr  ，删除对象中的，属性及方法

class Dog(object):
    '''
    dog class
    '''
    class_shuxing="hehe"
    def __init__(self,name):
        self.name=name
        self.age=None
        self.__sex=None

    def walk(self):
        print("%s is walking..." %self.name)


    def eat(self,food):
        print("%s is eating %s" %(self.name,food))

    def age(self,age):
        self.age=age

    def sex(self):
        return self.__sex

def bulk(self):
    print("%s is bulking..." %self.name)

d=Dog("NIUBI")
str=input("pls input:").strip()
if hasattr(d,str):
    v=getattr(d,str)
    print(v)
delattr(d,str)
print(hasattr(d,str))

-----

pls input:name
NIUBI
False