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On Python 3.5.0:
>>> from collections import namedtuple >>> cluster = namedtuple('Cluster', ['a', 'b']) >>> c = cluster(a=4, b=9) >>> c Cluster(a=4, b=9) >>> vars(c) OrderedDict([('a', 4), ('b', 9)]) On Python 3.5.1:
>>> from collections import namedtuple >>> cluster = namedtuple('Cluster', ['a', 'b']) >>> c = cluster(a=4, b=9) >>> c Cluster(a=4, b=9) >>> vars(c) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: vars() argument must have __dict__ attribute Seems like something about namedtuple changed (or maybe it was something about vars()?).
Was this intentional? Are we not supposed to use this pattern for converting named tuples into dictionaries anymore?
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Since a named tuple is a tuple, and tuples are immutable, it is impossible to change the value of a field.
Namedtuple makes your tuples self-document. You can easily understand what is going on by having a quick glance at your code. And as you are not bound to use integer indexes to access members of a tuple, it makes it more easy to maintain your code.
In general, you can use namedtuple instances wherever you need a tuple-like object. Named tuples have the advantage that they provide a way to access their values using field names and the dot notation. This will make your code more Pythonic.
Tuples are immutable, whether named or not. namedtuple only makes the access more convenient, by using names instead of indices. You can only use valid identifiers for namedtuple , it doesn't perform any hashing — it generates a new type instead.
Per Python bug #24931:
[
__dict__] disappeared because it was fundamentally broken in Python 3, so it had to be removed. Providing__dict__broke subclassing and produced odd behaviors.
Revision that made the change
Specifically, subclasses without __slots__ defined would behave weirdly:
>>> Cluster = namedtuple('Cluster', 'x y') >>> class Cluster2(Cluster): pass >>> vars(Cluster(1,2)) OrderedDict([('x', 1), ('y', 2)]) >>> vars(Cluster2(1,2)) {} Use ._asdict().
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