[Py]python str GetAttr Special method

Custom Input Instance name output

def __str__ will customize the output of the output instance name

class Chain(object):    def __str__(self):        return "hello"c = Chain()print(c) #本来是<__main__.Chain object at 0x00000000021BE5C0># hello  

Pass def __str__Output Property Name

class Chain(object):    def __init__(self):        self.name = "maotai"    def __str__(self):        return self.namec = Chain()print(c)# maotai

__getattr__Print any property, such as C.xx,c.yy

The main purpose is to implement dynamic add properties

class Chain(object):    # 打印c.xx属性    def __getattr__(self, item):        return itemc = Chain()print(c.xx)#xxx

class Chain(object):    def __init__(self):        self.name = "maotai"    # 打印c.xx属性时候返回定制内容    def __getattr__(self, item):        return item, self.namec = Chain()print(c.xx)# ('xx', 'maotai')

Profiling Print Results

class Chain(object):    def __init__(self, path=""):        self.__path = path    def __str__(self):        return self.__path  ## 打印Chain()的内容    def __getattr__(self, item):        # Chain("%s/%s" % (self.__path, item))即 __str__的结果        return Chain("%s/%s" % (self.__path, item))  ## 打印c.xx时, 返回Chain()的内容c = Chain()#c.xx       的结果 Chain("/xx")print(c.xx)

class Chain(object):    def __init__(self, path=""):        self.__path = path        print(self.__path, "++++")    def __str__(self):        # print(self.__path,"--------")        return self.__path  ## 打印Chain()的内容    def __getattr__(self, item):        # Chain("%s/%s" % (self.__path, item))获取到的是 self.__path内容,供__getattr__返回.        # self.__path的内容是 ("%s/%s" % (self.__path, item))        # 第1次 self.__path="/xx",   供__getattr__返回.        # 第2次 self.__path="/xx/yy",供__getattr__返回.        # 第3次 self.__path="/xx/zz",供__getattr__返回.        # return Chain()        # return Chain("/xx")        # return Chain("/xx/yy")        # return Chain("/xx/yy/zz")        return Chain("%s" % (item))  ## 打印c.xx时, 返回Chain()的内容c = Chain()#c.xx       的结果 Chain("/xx")#c.xx.yy    的结果 Chain("/xx/yy")#c.xx.yy.zz 的结果 Chain("/xx/yy/zz")print(c.xx.yy.zz)# /xx/yy/zz

[Py]python str GetAttr Special method