Why does Python not support record type? (i.e. mutable namedtuple)

Question

Why does Python not support a record type natively? It\'s a matter of having a mutable version of namedtuple.

I could use namedtuple._replace. But I nee

Answer 1

As tzot stated, since Python ≥3.3, Python does have a mutable version of namedtuple: types.SimpleNamespace.

These things are very similar to the new C# 9 Records.

Here are some usage examples:

Positional constructor arguments

>>> import types
>>>
>>> class Location(types.SimpleNamespace):
...   def __init__(self, lat=0, long=0):
...     super().__init__(lat=lat, long=long)
...
>>> loc_1 = Location(49.4, 8.7)

Pretty repr

>>> loc_1
Location(lat=49.4, long=8.7)

Mutable

>>> loc_2 = Location()
>>> loc_2
Location(lat=0, long=0)
>>> loc_2.lat = 49.4
>>> loc_2
Location(lat=49.4, long=0)

Value semantics for equality

>>> loc_2 == loc_1
False
>>> loc_2.long = 8.7
>>> loc_2 == loc_1
True

Can add attributes at runtime

>>> loc_2.city = 'Heidelberg'
>>> loc_2