[Tutor] How to have unique identifiers for multiple object instances of a given class?

[Mats Wichmann]

since your data is somewhat heirarchical - you have records for each game, which can contain from zero to many score records - please consider looking at json or yaml over csv for your persistent storage.  they're no harder to program for in Python, and in addition to representing the style of your data better, are more readable as the fields are named. more bulky certainly.

On August 26, 2018 9:58:34 PM MDT, boB Stepp <robertvstepp at gmail.com> wrote:
>On Sun, Aug 26, 2018 at 6:10 PM Alan Gauld via Tutor <tutor at python.org>
>wrote:
>>
>> On 26/08/18 23:38, boB Stepp wrote:
>>
>> > class SolitaireGame():
>> >     def __init__(self, name):
>> >         self.name = name
>>
>> > Say I go with the aforementioned game with 13 separate scores to
>keep
>> > track of.  The names of these games might be "Two_Mastery",
>> > "Three_Mastery", ... , "Ace_Mastery".  In principle I want 13
>objects
>> > with each one keeping track of each of the above games.  Then I
>might
>> > want to switch to "Spider_Solitaire", keep track of its score, then
>go
>> > to something else, then back to Mastery, etc.  How on earth am I to
>> > generate unique identifiers for each of these SolitaireGame objects
>in
>> > a rational way, not knowing in advance moment to moment what type
>of
>> > solitaire game I might be playing?
>>
>> A dictionary of objects keyed by name?
>
>So you are saying do something like:
>
>class SolitaireGame():
>    def __init__(self, name):
>        self.name = name
>
>    def describe_self(self):
>        print("This game of solitaire is called", self.name, ".")
>
>game_objects = {}
>def make_new_game_object(name):
>    global game_objects
>    game_objects[name[ = SolitaireGame(name)
>
>make_new_game_object('Chinese Solitaire')
>make_new_game_object('Ace Mastery')
>make_new_game_object('King Mastery')
>make_new_game_object('Spider')
>
>If I run the above in the interactive interpreter:
>3.6.6:  game_objects
>{'Chinese Solitaire': <__main__.SolitaireGame object at
>0x7f3991d5e400>, 'Ace Mastery': <__main__.SolitaireGame object at
>0x7f3991d5e470>, 'King Mastery': <__main__.SolitaireGame object at
>0x7f3991d5e438>, 'Spider': <__main__.SolitaireGame object at
>0x7f3991d5e4e0>}
>3.6.6:  game_objects['Spider'].describe_self()
>This game of solitaire is called Spider.
>
>This would seem to work, though I would have to be very careful to not
>allow the user to create a new game with the same name (Now a key.)
>which would overwrite an already existing game object.
>
>> If using a GUI add the names to a drop down or listbox
>> to ease later selection.
>
>Ultimately I would add a GUI interface.
>
>> Does that work for you?
>
>If what I wrote above describes what you intend, then yes.
>
>> > between them at will.  Of course the intent is to persistently
>store
>> > these objects on disk upon program closure.
>>
>> Maybe JSON for that? Or even a shelve database?
>
>I plan to keep this simple.  I will use a ".cfg" file to store game
>configuration information and a ".csv" file to store the actual
>records of hands played.  But I will have to be careful how I generate
>the base filenames to avoid duplicates and potential nasty
>user-generated names.  Though this project is only meant for my use
>...
>
>
>
>-- 
>boB
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