Object-oriented-reflection of Python

First, what is reflection

The concept of reflection was first proposed by Smith in 1982, mainly referring to the ability (introspection) of a program to access, detect, and modify its state or behavior in the province. The proposal of this concept soon triggered the research on the application of reflectivity in Computer science field. It is first used in the field of programming language design, and has achieved achievements in Lisp and object-oriented.

Python-oriented reflection in objects: manipulating Object-related properties in the form of strings. Everything in Pythonn is an object (you can use reflection)

Four methods of reflection

Everything is object, and the class itself is an object

Hasattr

def hasattr(*args, **kwargs): # real signature unknown    """    Return whether the object has an attribute with the given name.        This is done by calling getattr(obj, name) and catching AttributeError.    """    pass

GetAttr

def getattr(object, name, default=None): # known special case of getattr    """    getattr(object, name[, default]) -> value        Get a named attribute from an object; getattr(x, 'y') is equivalent to x.y.    When a default argument is given, it is returned when the attribute doesn't    exist; without it, an exception is raised in that case.    """    pass

SetAttr

def setattr(x, y, v): # real signature unknown; restored from __doc__    """    Sets the named attribute on the given object to the specified value.        setattr(x, 'y', v) is equivalent to ``x.y = v''    """    pass

Delattr

def delattr(x, y): # real signature unknown; restored from __doc__    """    Deletes the named attribute from the given object.        delattr(x, 'y') is equivalent to ``del x.y''    """    pass

Third, the case

class Foo:    f = '类的静态变量'    def __init__(self,name,age):        self.name=name        self.age=age    def say_hi(self):        print('hi,%s'%self.name)obj=Foo('john',73)#检测是否含有某属性print(hasattr(obj,'name'))print(hasattr(obj,'say_hi'))#获取属性n=getattr(obj,'name')print(n)func=getattr(obj,'say_hi')func()print(getattr(obj,'aaaaaaaa','不存在啊')) #报错#设置属性setattr(obj,'sb',True)setattr(obj,'show_name',lambda self:self.name+'sb')print(obj.__dict__)print(obj.show_name(obj))#删除属性delattr(obj,'age')delattr(obj,'show_name')delattr(obj,'show_name111')#不存在,则报错print(obj.__dict__)

Object-oriented-reflection of Python