《Python》反射、内置方法（__str__，__repr__）

一、反射

　　　通过字符串的形式操作对象相关的属性。（使用字符串数据类型的变量名来获取这个变量的值）

　　　　Python中的一切事物都是对象（都可以使用反射）

　　　　　　反射类中的变量

　　　　　　反射对象中的变量

　　　　　　反射模板中的变量

　　　　　　反射本文件中的变量

　　　　用反射的场景：

　　　　　　input

　　　　　　网络

　　　　　　文件

#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

反射的4种方法源码