I was just copying the benchmark I was quoting as a sanity check since I was just trying to validate references. I also feel compelled to point out that __slot

I was just copying the benchmark I was quoting as a sanity check since I was just trying to validate references. I also feel compelled to point out that __slots__ changes the way objects are initialized [1]: > By default, instances of both old and new-style classes have a dictionary for attribute storage. This wastes space for objects having very few instance variables. The space consumption can become acute when creating large numbers of instances. > > The default can be overridden by defining __slots__ in a new-style class definition. The __slots__ declaration takes a sequence of instance variables and reserves just enough space in each instance to hold a value for each variable. Space is saved because __dict__ is not created for each instance. Which means that, in actuality, simply defining __slots__ changes the nature of the object. Quick trial demonstrates this: >>> class mySlottedObj(object): ... __slots__ = ('a', 'b') ... c = 1 ... >>> x = mySlottedObj() >>> x <mySlottedObj object at 0x10e6a3510> >>> x.c 1 >>> x.__dict__ Traceback (most recent call last): File "<input>", line 1, in <module> AttributeError: 'mySlottedObj' object has no attribute '__dict__' >>> x.__weakref__ Traceback (most recent call last): File "<input>", line 1, in <module> AttributeError: 'mySlottedObj' object has no attribute '__weakref__' >>> x.a = 1 >>> x.c = 2 Traceback (most recent call last): File "<input>", line 1, in <module> AttributeError: 'mySlottedObj' object attribute 'c' is read-only The benefit of namedtuples, in the context of Python is reducing the object footprint to being no greater than a tuple. The performance hit, which I am trying to demonstrate, is in lookup and is shown in the source (linked above). _field_template = '''\ {name} = _property(_itemgetter({index:d}), doc='Alias for field number {index:d}') ''' As I understand it this means when you access using __getitem__, a named tuple first maps to a property that then calls a __getitem__ using the aliased index on the base `tuple` object that `namedtuple` is storing. But at any rate, the benchmark script was not mine and refining the test to be as close to the same code path is welcome. And I wholeheartedly agree: > Only if you're too slow, then you look for ways to optimize for bottlenecks. I was merely responding to the original assertion: > This provides the same performance benefits, and is very similar in a lot of ways to a Scala case class -- aside from removing the boilerplate of stating each attribute twice in __init__ and again in __slots__, And I think at this point it is quite clear that namedtuple has a bit more caveats than just "removing the boilerplate" of __slots__.