On Aug 21, 2007, at 2:14 PM, Brendan Arnold wrote:
> > hi there, > > i'd like to add an array of 'tag' attributes for use on my orm objects > while my scripts are running (i.e. a flag to delete etc.). > > recently i found that, > > class Foo(object): > tags = [] > > caused problems with object instances sharing the same .tags attribute > list. to ensure that a new instance was created on instantiation i > started doing, > > class Foo(object): > def __init__(self): > self.tags = [] > > however the init behaviour of sqlalchemy is altered, see > http://www.sqlalchemy.org/trac/wiki/ > FAQ#whyisntmy__init__calledwhenIloadobjects > > i realise that there is a way around this described in the sqlalchemy > faq, but since i am a relative python newbie i was wondering if there > is a better way to ensure each one of my instances has a fresh list > created? > a common technique is to use a property: class MyClass(object): def _init_attr(self): if not hasattr(self, '_foo'): self._foo = [] return self._foo foo = property(_init_attr) --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
