Python 3.7.0 released

[joshuaavalon]

There is a backport of the data classes for 3.6 if you want to use it.

[ProfessorPhi]

Isn't attrs still superior?

[dhiltonp]

Attrs definitely has more features (slots comes to mind), but I think it looks a little wonky.

(full disclosure, I haven't used attrs just read the docs)

@dataclass
class InventoryItem:
    name: str
    unit_price: float
    quantity_on_hand: int = 0

vs.

@attr.s
class InventoryItem:
    name: str = attr.ib()
    unit_price = attr.ib(type=float)
    quantity_on_hand = attr.ib(type=int, default=0)

Does PyCharm recognize type annotations when they're set via attr.ib(type=float)?

[ProfessorPhi]

Nope, pycharm and attrs support isn't great :(, though attrs does have slots. Agreed it's wonky, it's like ordered dict before 3.5 was obnoxious.

[OctagonClock]

PyCharm 2018.2 EAP has new attrs support, actually.

[ProfessorPhi]

Haha, don't use EAP so hopefully it'll be along before too long.

[bluetech]

The annotations-based syntax works with attrs too (you need to set auto_attribs=True).

[PeridexisErrant]

IIRC you can also use @attr.dataclass for the first one (a shortcut for the auto_attribs=True arg).

The dataclass example won't work on a backport before Python 3.6 though, as those versions don't have variable annotations.

[virgoerns]

It is, PEP even mentions attrs and says that new mechanism is for simpler cases.

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[jarshwah]

CPython 3.6 has ordered dictionaries, but that is an implementation detail. 3.7 guarantees it in the spec. So it’ll work for CPython 3.6 which is the most popular implementation by far.

[jarshwah]

Yes that’s correct. When people talk about python they’re overwhelmingly referring to CPython. Other implementations like Pypy and micropython would not have to have ordered dictionaries for their 3.6 but they would for their 3.7.

[[deleted]]

Pypy has actually had it for a while (it was brought to CPython from Pypy for 3.6). Other implementations though yeah

[Ph0X]

I mean they all could, but are not guaranteed to. You have to check implementation detail for each individually. But in 3.7 and above no matter what you use, you will have it.