day25反射

s15day25 面向对象相关
 
内容回顾:
    1. 昨日知识点
        - 特殊成员
        - 组合嵌套
        - 主动调用其他类成员
            - super
    2. 列举特殊成员
        __enter__
        __exit__
        __call__
        __getitem__,obj['xx']
        __setitem__,obj['xx'] = 1
        __delitem__,del obj['xx']
        __new__,
        __init__
        __add__
        
        __str__
            class Foo(object):
                def __init__(self):
                    pass
 
                def func(self):
                    pass
 
                def __str__(self):
                    return "F1"
 
            obj = Foo()
            print(obj,type(obj))
        __doc__
            
            class Foo(object):
                """
                asdfasdfasdfasdf
                """
                def __init__(self):
                    pass
 
                def func(self):
                    pass
 
                def __str__(self):
                    return "F1"
 
            obj = Foo()
            print(obj.__doc__)
        __dict__
            
            class Foo(object):
                def __init__(self,name,age):
                    self.name = name
                    self.age = age
 
                def func(self):
                    pass
 
            obj1 = Foo('刘博文',99)
            obj2 = Foo('史雷',89)
 
 
            print(obj1.__dict__) # {'name': '刘博文', 'age': 99}
            print(obj2.__dict__) # {'name': '史雷', 'age': 89}
        __iter__
            # l1是list类的一个对象,可迭代对象
            l1 = [11,22,33,44]
 
            # l2是list类的一个对象,可迭代对象
            l2 = [1,22,3,44]
 
 
            class Foo(object):
                def __init__(self,name,age):
                    self.name = name
                    self.age = age
 
                def func(self):
                    pass
 
                def __iter__(self):
                    # return iter([11,22,33,44,55,66])
 
                    yield 11
                    yield 22  
                    yield 33
 
            # obj1是Foo类的一个对象,可迭代对象
            """
            如果想要把不可迭代对象 -> 可迭代对象
            1. 在类中定义__iter__方法
            2. iter内部返回一个迭代器(生成器也是一种特殊迭代器)
            """
            obj1 = Foo('刘博文',99)
 
            for item in obj1:
                print(item)
    3. 练习题:...
        
今日内容:
    1. isinstance/issubclass/type
    
    2. 方法和函数
    
    3. 反射
    
    4. 其他
    
内容详细:
    1. issubclass/type/isinstance/
    
        issubclass
            class Base(object):
                pass
 
            class Foo(Base):
                pass
 
            class Bar(Foo):
                pass
 
            print(issubclass(Bar,Base)) # 检查第一个参数是否是第二个参数的 子子孙孙类
            
        type:获取当前对象是由那个类创建。
                """
                class Foo(object):
                    pass
 
                obj = Foo()
 
                print(obj,type(obj)) # 获取当前对象是由那个类创建。
                if type(obj) == Foo:
                    print('obj是Foo类型')
                """
 
                # #### 练习题
                """
                class Foo(object):
                    pass
 
                class Bar(object):
                    pass
 
                def func(*args):
                    foo_counter =0
                    bar_counter =0
                    for item in args:
                        if type(item) == Foo:
                            foo_counter += 1
                        elif type(item) == Bar:
                            bar_counter += 1
                    return foo_counter,bar_counter
 
                # result = func(Foo(),Bar(),Foo())
                # print(result)
 
                v1,v2 = func(Foo(),Bar(),Foo())
                print(v1,v2)
                """
            
        isinstance,检查第一个参数(对象)是否是第二个参数(类及父类)的实例。
                        
            class Base(object):
                pass
 
            class Foo(Base):
                pass
 
            obj1 = Foo()
            print(isinstance(obj1,Foo))  # 检查第一个参数(对象)是否是第二个参数(类及父类)的实例。
            print(isinstance(obj1,Base)) # 检查第一个参数(对象)是否是第二个参数(类及父类)的实例。
 
 
            obj2 = Base()
            print(isinstance(obj2,Foo))  # 检查第一个参数(对象)是否是第二个参数(类及父类)的实例。
            print(isinstance(obj2,Base)) # 检查第一个参数(对象)是否是第二个参数(类及父类)的实例。
 
 
 
            # #################### 练习
            """
            给你一个参数,判断对象是不是由某一个指定类? type                  --> type(obj) == Foo
            给你一个参数,判断对象是不是由某一个指定类或其父类? isinstance    --> instance(obj,Foo)
            """
        
        
    2. 方法和函数
        称谓:
            类,方法
            外,函数
        到底方法函数?
            对象.xxx  --> xxx就是方法
            类.xxx    --> xxx就是函数
            xxx       --> xxx就是函数
        打印查看:
            function
            method
            
        代码检查:
            from types import MethodType,FunctionType
            def check(arg):
                """
                检查arg是方法还是函数?
                :param arg:
                :return:
                """
                if isinstance(arg,MethodType):
                    print('arg是一个方法')
                elif isinstance(arg,FunctionType):
                    print('arg是一个函数')
                else:
                    print('不知道是什么')
        
    
    3. 反射
        a. 需求
        
        总结:
            v = getattr(obj,"func")  # 根据字符串为参数(第二个参数),去对象(第一个参数)中寻找与之同名的成员。
            
        练习题:    
            ..
            
        好记:
            getattr # 根据字符串的形式,去对象中找成员。
            hasattr # 根据字符串的形式,去判断对象中是否有成员。
            setattr # 根据字符串的形式,动态的设置一个成员(内存)
            delattr # 根据字符串的形式,动态的删除一个成员(内存)
        应用一:
            # by luffycity.com
            from types import FunctionType
            import handler
 
            while True:
                print("""
                系统支持的函数有:
                    1. f1
                    2. f2
                    3. f3
                    4. f4
                    5. f5
                """)
                val = input("请输入要执行的函数:") # val = "f1"
 
                # 错误
                # handler.val()
                if hasattr(handler,val):
                    func_or_val = getattr(handler,val)     # 根据字符串为参数,去模块中寻找与之同名的成员。
                    if isinstance(func_or_val,FunctionType):
                        func_or_val()
                    else:
                        print(func_or_val)
                else:
                    print('handler中不存在输入的属性名')
 
                # 正确方式
                """
                if val == 'f1':
                    handler.f1()
                elif val == 'f2':
                    handler.f2()
                elif val == 'f3':
                    handler.f3()
                elif val == 'f4':
                    handler.f4()
                elif val == 'f5':
                    handler.f5()
                """
        
        应用二:
            
            class Account(object):
                func_list = ['login', 'logout', 'register']
 
                def login(self):
                    """
                    登录
                    :return:
                    """
                    print('登录111')
 
                def logout(self):
                    """
                    注销
                    :return:
                    """
                    print('注销111')
 
                def register(self):
                    """
                    注册
                    :return:
                    """
                    print('注册111')
 
                def run(self):
                    """
                    主代码
                    :return:
                    """
                    print("""
                        请输入要执行的功能:
                            1. 登录
                            2. 注销
                            3. 注册
                    """)
 
                    choice = int(input('请输入要执行的序号:'))
                    func_name = Account.func_list[choice-1]
 
                    # func = getattr(Account,func_name) # Account.login
                    # func(self)
 
                    func = getattr(self, func_name)  # self.login
                    func()
 
            obj1 = Account()
            obj1.run()
 
            obj2 = Account()
            obj2.run()
        
总结:
    
    反射 *****
    issubclass/type/isinstance/ ***
    方法和函数 *
        
    问题:你见过的什么后面可以加()?
            - 类()
            - 对象()
            - 函数()
            - 方法()
            以上所有都可以被调用。
            
    示例:
        def func():
            pass
 
 
        class Foo(object):
            def __call__(self, *args, **kwargs):
                pass
            def func(self):
                pass
        obj = Foo()
 
 
        print(callable(func))
        print(callable(Foo))
        print(callable(obj))
        print(callable(obj.func))
            
作业:
    
class FOO(object):
    "doc neirong "
    def __init__(self,name):
        self.name=name
        pass
    def func(self):
        age=10
        return age
    def __str__(self):
        return 'FOOTEST'

    def __iter__(self):
        # return iter([1,2,3,4,5,6,7,8,9])
        yield 11
        yield 33
        yield 44
obj1=  FOO('walker')
print(obj1,type(obj1))
print(obj1.__doc__)
print(obj1.__dict__)
#   __dict__  将类的对象中所有的封装的值以字典的形式返回
#   __doc 返回类的注释相关信息
#   类中__str__ 方法;print时返回这个类的 __str__的返回值,
#   若是没有 __str方法则直接返回类的内存地址
#   可以加type查看是对象还是其它类型
# ---------------------
# 如果想要把不可迭代对象 -> 可迭代对象
# 1. 在类中定义__iter__方法
# 2. iter内部返回一个迭代器(生成器也是一种特殊迭代器)
for i in obj1:
    print(i)

# by luffycity.com
""""""
# 第一题:

# class StarkConfig(object):
#     list_display = []
#
#     def get_list_display(self):
#         self.list_display.insert(0,33)
#         return self.list_display
#
# class RoleConfig(StarkConfig):
#     list_display = [11,22]
#
#
# s1 = StarkConfig()
#
# result1 = s1.get_list_display()
# print(result1) # 33
#
# result2 = s1.get_list_display()
# print(result2) # 33 33


# -------------------------
# class StarkConfig(object):
#     def __init__(self):
#         self.list_display = []
#
#     def get_list_display(self):
#         self.list_display.insert(0, 33)
#         return self.list_display
#
#
# class RoleConfig(StarkConfig):
#     list_display = [11, 22]
#
#
# s1 = StarkConfig()
#
# result1 = s1.get_list_display()
# print(result1)  # 33
#
# result2 = s1.get_list_display()
# print(result2)  # 33 33
# ------------------------

# class StarkConfig(object):
#     def __init__(self):
#         self.list_display = []
#
#     def get_list_display(self):
#         self.list_display.insert(0, 33)
#         return self.list_display
#
#
# class RoleConfig(StarkConfig):
#     list_display = [11, 22]
#
#
# s1 = StarkConfig()
# s2 = StarkConfig()
#
# result1 = s1.get_list_display()
# print(result1)  # 33
#
# result2 = s2.get_list_display()
# print(result2)  # 33

# ---------------------------#
# class StarkConfig(object):
#     list_display = []
#
#     def get_list_display(self):
#         self.list_display.insert(0, 33)
#         return self.list_display
#
#
# class RoleConfig(StarkConfig):
#     list_display = [11, 22]
#
#
# s1 = StarkConfig()
# s2 = StarkConfig()
#
# result1 = s1.get_list_display()
# print(result1)  # 33
#
# result2 = s2.get_list_display()
# print(result2)  # 33 33


# ############################################################################################

# 第二题:

# class StarkConfig(object):
#     list_display = []
#
#     def get_list_display(self):
#         self.list_display.insert(0,33)
#         return self.list_display
#
# class RoleConfig(StarkConfig):
#     list_display = [11,22]
#
#
# s1 = StarkConfig()
# s2 = StarkConfig()
#
# result1 = s1.get_list_display()
# print(result1)
#
# result2 = s2.get_list_display()
# print(result2)


# 第三题:
"""
class StarkConfig(object):
    list_display = []

    def get_list_display(self):
        self.list_display.insert(0,33)
        return self.list_display

class RoleConfig(StarkConfig):
    list_display = [11,22]


s1 = StarkConfig()
s2 = RoleConfig()

result1 = s1.get_list_display()
print(result1)

result2 = s2.get_list_display()
print(result2)
"""

# 第四题:
# """
class StarkConfig(object):
    list_display = []

    def get_list_display(self):
        self.list_display.insert(0,33)
        return self.list_display

class RoleConfig(StarkConfig):
    list_display = [11,22]


s1 = RoleConfig()
s2 = RoleConfig()

result1 = s1.get_list_display()
print(result1)

result2 = s2.get_list_display()
print(result2)
# """        
        
   class Base(object):
    pass

class Foo(Base):
    pass

class Bar(Foo):
    pass

print(issubclass(Bar,Base)) # 检查第一个参数是否是第二个参数的 子子孙孙类
        
        

        
        
class Foo(object):
    pass

obj = Foo()

print(obj,type(obj)) # 获取当前对象是由那个类创建。
if type(obj) == Foo:
    print('obj是Foo类型')    
class Base(object):
    pass

class   Foo(Base):
    pass
obj1=Foo()
print(isinstance(obj1,Foo))  # 检查第一个参数(对象)是否是第二个参数(类及父类)的实例。
print(isinstance(obj1,Base))  # 检查第一个参数(对象)是否是第二个参数(类及父类)的实例。
obj2=Base()
print(isinstance(obj2,Foo))   # 检查第一个参数(对象)是否是第二个参数(类及父类)的实例。
print(isinstance(obj2,Base)) 
给你一个参数,判断对象是不是由某一个指定类? type --> type(obj) == Foo
给你一个参数,判断对象是不是由某一个指定类或其父类? isinstance --> instance(obj,Foo)

from types import MethodType,FunctionType

def check(arg):
    """
    检查arg是方法还是函数?
    :param arg:
    :return:
    """
    if isinstance(arg,MethodType):
        print('arg是一个方法')
    elif isinstance(arg,FunctionType):
        print('arg是一个函数')
    else:
        print('不知道是什么')

def func():
    pass

class Foo(object):
    def detail(self):
        print("detail")
        pass
    @staticmethod
    def xxx():
        pass

check(func)

obj = Foo()
check(obj.detail)
check(obj.xxx)
反射示例
from types import MethodType,FunctionType
import  handler

while True:
    val=input("要执行的函数名")
    if hasattr(handler,val):            # 根据字符串为参数,去类中寻找与之同名的成员。
        fun=getattr(handler,val)           ##  根据字符串为参数,去类中寻找与之同名的成员。
        if isinstance(fun,FunctionType):
            print("是个函数马上执行")
            fun()
        else:
            print("不是函数,是个普通的变量")
    else:
        print("不存在此函数")

        ---------------------------------------------
反射
class Foo(object):

    country = "中国"

    def func(self):
        pass

# v = getattr(Foo,'func') # Foo.func # 根据字符串为参数,去类中寻找与之同名的成员。
# print(v)

# obj = Foo()
# v = getattr(obj,"func") # obj.func # 根据字符串为参数,去对象中寻找与之同名的成员。
# print(v)
getattr # 根据字符串的形式,去对象中找成员。
hasattr # 根据字符串的形式,去判断对象中是否有成员。
setattr # 根据字符串的形式,去判断对象动态的设置一个成员(内存)
delattr # 根据字符串的形式,去判断对象动态的设置一个成员(内存)
"""
class Foo(object):

    def __init__(self,a1):
        self.a1 = a1
        self.a2 = None

obj = Foo(1)

v1 = getattr(obj,'a1')
print(v1)

setattr(obj,'a2',2)   #设置变量;最好不用在类中使用,但是原变量名一定要在文件中显示,不然其他人看不出来你的变量

v2 = getattr(obj,'a2')   
print(v2)        
        
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原文地址:https://www.cnblogs.com/pythonwork/p/11923411.html