As the author of `recordclass` I would like to shed some light...
Recorclass originated as a response to the
[question](https://stackoverflow.com/questions/29290359/existence-of-mutable-named-tuple-in-python/29419745#29419745)
on stackoverflow.
`Recordclass` was conceived and implemented as a type that, by api, memory
and speed, would be completely identical to` namedtuple`, except that it
would support an assignment in which any element could be replaced without
creating a new instance, as in ` namedtuple`. Those. would be almost
identical to `namedtuple` and support the assignment (` __setitem__` /
`setslice__`).
The effectiveness of namedtuple is based on the effectiveness of the
`tuple` type in python. In order to achieve the same efficiency it was
necessary to create a type `memoryslots`. Its structure
(`PyMemorySlotsObject`) is identical to the structure of` tuple`
(`PyTupleObject`) and therefore takes up the same amount of memory as`
tuple`.
`Recordclass` is defined on top of` memoryslots` just like `namedtuple`
above` tuple`. Attributes are accessed via a descriptor (`itemgetset`),
which supports both` __get__` and `__set__` by the element index.
The class generated by `recordclass` is:
`` `
from recordclass import memoryslots, itemgetset
class C (memoryslots):
__slots__ = ()
_fields = ('attr_1', ..., 'attr_m')
attr_1 = itemgetset (0)
...
attr_m = itemgetset (m-1)
def __new __ (cls, attr_1, ..., attr_m):
'Create new instance of {typename} ({arg_list})'
return memoryslots .__ new __ (cls, attr_1, ..., attr_m)
`` `
etc. following the `namedtuple` definition scheme.
As a result, `recordclass` takes up as much memory as` namedtuple`, it
supports quick access by `__getitem__` /` __setitem__` and by attribute
name via the protocol of the descriptors.
Regards,
Zaur
суббота, 1 сентября 2018 г., 10:48:07 UTC+3 пользователь Martin Bammer
написал:
>
> Hi,
>
> what about adding recordclass
> (https://bitbucket.org/intellimath/recordclass) to the collections module
>
> It is like namedtuple, but elements are writable and it is written in C
> and thus much faster.
>
> And for convenience it could be named as namedlist.
>
> Regards,
>
> Martin
>
>
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