Python内置函数--getattr&setattr&delattr&hasattr

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

class Attr:
    name = "清安"
res = getattr(Attr,'name')
print(res)
attr = Attr.name
print(attr)
"""
清安
清安
"""

class Attr:
    name = "清安"
res = getattr(Attr,'QA','找不到这个名字')
print(res)
"""找不到这个名字"""

class Attr:
    name = "清安"
    def information(self, age: int):
        return f"{self.name}今年{age}岁了"
res = getattr(Attr(),'information','找不到这个名字')(60)
print(res)
"""清安今年60岁了"""

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

class Attr:
    name = "清安"
    def information(self, age):
        return f"{self.name}今年{age}岁了"
setattr(Attr,"name",'拾贰')
print(Attr.name)
set = Attr.name = "拾贰长大了"
print(set)
"""
拾贰
拾贰长大了
"""

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

class Attr:
    name = "清安"
    def infomation(self,age):
        return f"{self.name}今年{age}岁了！"
res = delattr(Attr,'name')
print(res)
attr = Attr().infomation(18)
print(attr)
"""
None
AttributeError: 'Attr' object has no attribute 'name'
"""

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

class Attr:
    name = "清安"
    def infomation(self,age):
        return f"{self.name}今年{age}岁了！"
res = hasattr(Attr,'name')
print(res)
"""True"""

class Attr:
    name = "清安"
    def infomation(self,age):
        return f"{self.name}今年{age}岁了！"
if hasattr(Attr,'name'):
    res = getattr(Attr,"name")
    print(res)