On Mon, May 18, 2009 at 5:24 PM, Karen Tracey <[email protected]> wrote:
> On Mon, May 18, 2009 at 6:53 PM, Mohan Parthasarathy > <[email protected]>wrote: > >> Hi, >> >> class CategoryAdmin(admin.ModelAdmin): >> prepopulated_fields = {'slug' : ('title', )} >> >> Why does the format require a comma after "title'. It is still a valid >> tuple without a comma, right ? > > > No, it's a string. Single-element tuples require a trailing comma (more > than they require the parens, actually). See: > http://docs.python.org/tutorial/datastructures.html#tuples-and-sequences > > >> Without that, I keep getting errors. >> > > You're actually lucky there. Often these sneak by without an immediate > error, and at some point way later some code iterates over your "tuple", > producing, since strings are iterable too, the unexpected sequence 't', 'i', > 't', 'l', 'e'. That sort of thing often leads to much harder to find > bugs....or maybe that's the error you encountered? > > >> >> Sorry, If this was a dumb question. I am parallely doing python and >> django. Atleast creating a dictionary in python did not require a comma for >> the tuple >> > > Not dumb...it's a Python gotcha that routinely trips up newcomers to the > language. I'd recheck that your dictionary-creation code is actually > creating what you want. It may look like it's working but lead to problems > down the line if you are missing trailing commas on what are supposed to be > single-element tuples. > Thanks a lot. Though the dictionary was created, I did not bother to check whether it was a string or a tuple. Thanks again! mohan > > Karen > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
