Laszlo Nagy wrote:
> Given this iterator:
>
> class SomeIterableObject(object):
> ....
> ....
>
> def __iter__(self):
> ukeys = self.updates.keys()
> for key in ukeys:
> if self.updates.has_key(key):
> yield self.updates[key]
> for rec in self.inserts:
> yield rec
> ....
> ....
>
> How can I get this exception:
>
> RuntimeError: dictionary changed size during iteration
>
>
> It is true that self.updates is being changed during the iteration. But
> I have created the "ukeys" variable solely to prevent this kind of
> error. Here is a proof of correctness:
>
>>>> d = {1:1,2:2}
>>>> k = d.keys()
>>>> del d[1]
>>>> k
> [1, 2]
>>>> k is d.keys()
> False
>
> So what is wrong with this iterator? Why am I getting this error message?
`ukeys` isn't a different dictionary from `self.updates.keys` I'ts merely
another name referring to the same dict object. I think
ukeys = dict (self.updates.keys)
would do what you want.
Mel.
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