Albert-Jan Roskam <sjeik_ap...@hotmail.com> writes:
> Why is an OrderedDict not sliceable?
Because slicing implies index access. The built-in ‘dict’ and
‘collections.OrderedDict’ both do not support indexed access::
>>> import collections
>>> foo = collections.OrderedDict([
... ('a', 1), ('b', 2), ('c', 3), ('d', 4)])
>>> foo[3]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
KeyError: 3
>>> bar = dict([
... ('a', 1), ('b', 2), ('c', 3), ('d', 4)])
>>> bar[3]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
KeyError: 3
Index access with ‘foo[index]’ syntax, and slicing with
‘foo[start_index:stop_index:step]’ syntax, collide with the existing
key-access meaning of ‘foo[key]’ for a mapping.
--
\ “[I]t is impossible for anyone to begin to learn that which he |
`\ thinks he already knows.” —Epictetus, _Discourses_ |
_o__) |
Ben Finney
_______________________________________________
Tutor maillist - Tutor@python.org
To unsubscribe or change subscription options:
https://mail.python.org/mailman/listinfo/tutor
