On Apr 7, 4:13 am, andrew cooke <and...@acooke.org> wrote:
> If you look at the code
> inhttp://hg.python.org/cpython/file/6adbf5f3dafb/Lib/collections/__init...the
> attribute __root is checked for, and only created if missing. Why?
>
> I ask because, from what I understand, the __init__ method will only be
> called when the object is first being created, so __root will always be
> missing.
First of all, three cheers for reading the source code!
A user can call __init__() even after the OrderedDict instance has
already been created. If so, the __root attribute will already exist
and the whole operation becomes equivalent to an update().
You can see the same behavior with regular dictionaries:
>>> d = dict(a=1, b=2)
>>> d.__init__(b=4, c=5)
>>> d
{'a': 1, 'c': 5, 'b': 4}
Raymond
--
http://mail.python.org/mailman/listinfo/python-list
