On Tue, 29 Sep 2015 02:27:23 -0700, plewto wrote:
> I have a perplexing problem with Python 3 class variables. I wish to
> generate an unique ID each time an instance of GameClass is created.
> There are two versions of the __gen_id method with test run results for
> each listed below the code.
>
> Originally I used the version which is now commented out. When a new
> instance was created it created an ID by appending the value of
> __instance_counter to the class name, it then checked the contents of of
> __instatance_registrty to see if this ID was already in use. If so it
> incremented the counter until it found an unused ID. This version works
> exactly as I expected.
>
> Later I decided to get rid of __instance_registry and rely solely on the
> restricted access to __instance_counter and the fact that it is
> monotonically increasing to generate IDs. I wrote the second, simpler
> version of __gen_id to that end, but it doesn't work! No doubt I'm
> overlooking something very simple here but I'm not seeing it.
>
> Any help appreciated.
>
>
> class GameObject:
>
> # __instance_registry = {"":None}
> __instance_counter = 0
>
> def __init__(self, name):
> self.__name = str(name)
> self.__id = self.__gen_id()
>
> # def __gen_id(self):
> # ty = self.__class__.__name__
> # id = ''
> # while id in self.__instance_registry:
> # id = '%s_%d' % (ty, self.__instance_counter)
> # self.__instance_counter += 1 #
> self.__instance_registry[id] = self # return id
>
> def __gen_id(self):
> ty = self.__class__.__name__
> id = '%s_%d' % (ty, self.__instance_counter)
> self.__instance_counter += 1 return id
>
> def __str__(self):
> return "name = '%s' id = '%s'" % (self.__name, self.__id)
>
>
> go1 = GameObject("GO1")
> go2 = GameObject("GO2")
> go3 = GameObject("GO3")
> print(go1)
> print(go2)
> print(go3)
>
>
> # Results with original __gen_id method # name = 'GO1' id =
> 'GameObject_0'
> # name = 'GO2' id = 'GameObject_1'
> # name = 'GO3' id = 'GameObject_2'
>
>
> # Results with new simpler __gen_id method, __instance_counter not being
> incremented # name = 'GO1' id = 'GameObject_0'
> # name = 'GO2' id = 'GameObject_0'
> # name = 'GO3' id = 'GameObject_0'
why reinvent the wheel?
why not simply use pythons builtin id function?
each new instance of an object is automatically assigned a unique ID
--
I'm a soldier, not a diplomat. I can only tell the truth.
-- Kirk, "Errand of Mercy", stardate 3198.9
--
https://mail.python.org/mailman/listinfo/python-list
