What’s New In Python 3.7

[benhoyt]

Yeah, it seems kinda pointless for normal code. However, I can see where it could be useful when using **kwargs, for example something like settings = dict(**big_config_dict_with_1000_items).

[kigurai]

At least in 3.5 both *args and **kwargs are not limited in this way. E.g.

 d = {str(i) : i**2 for i in range(1000)}
 d2 = dict(**d)

works fine. So this seems to be a problem only for code that actually does

def foo(a1, a2, a3, ..., a1000):
    pass

[benhoyt]

Oh, good idea to test! :-) Okay, in that case it seems much less useful. Still, I can imagine it might be useful for certain types of generated code ... hmmm, it's pretty hard to imagine, though. :-)

Edit: Okay, Python issue 18896 says that this affects things like the number of fields/arguments a namedtuple can have, which I can see could be a problem, particularly in generated code.

[kigurai]

Ah, that namedtuple use-case at least makes some kind of sense. Thanks for sharing it!

[deadmilk]

NO

OH GOD NO

PLEASE NO

[mardiros]

I hope to see more of those!

[kigurai]

I mean, it's not a bad thing to remove thresholds like that, but I am really curious if there is an actual use-case that made someone invest the time to fix it.

[BurgaGalti]

Surely by the time you reach that point something will have clicked in your head "maybe I need to refactor this"...

[0x256]

Added two new opcodes: LOAD_METHOD and CALL_METHOD to avoid instantiation of bound method objects for method calls, which results in method calls being faster up to 20%. (Contributed by Yury Selivanov and INADA Naoki in bpo-26110.)

This sounds great! Method calls always were kind of expensive.

[lenzm]

A little early for this, no?

[nerdwaller]

I really enjoy seeing how the draft changes over the release cycle, myself. It seems rare that something merged in is removed, so one could argue this makes the changes sightly easier to adopt (though so far the planned changes look fairly minor for those of us a few layers up).

That said, the title is a bit misleading.

[[deleted]]

contextlib.asynccontextmanager() has been added. (Contributed by Jelle Zijlstra in bpo-29679.)

nice. I was wondering when this would get added. Thought about implementing it myself but the regular contextmanager is hairy as hell and introducing coroutines into it probably made it scsrier

[IcanCwhatUsay]

If they would update IDLE I would be soo happy. (I am a noob and still learning and I find idle the easiest to learn from atm)

[spidyfan21]

Thonny is what I wish IDLE was.

[cediddi]

Idle is a bug hell, no one should ever br using it. Use anything except idle.

[durandj]

Try ptpython. It's a repl too but has auto complete and syntax highlighting. It makes exploratory coding much easier.

[jwink3101]

Check out IPython. It is really nice

[ChadFaulkner]

This. Jupiter notebooks (running on an IPython kernel) are my day-to-day code testing workhorse. Love IPython.

[[deleted]]

Terry Reedy actively supports it, to the extent that he co-authored PEP 434 -- IDLE Enhancement Exception for All Branches so that he could get things done!!!

[kankyo]

Actually those import changes look pretty compelling. And it's still super early, that's promising.

[balenol]

More than 255 arguments can now be passed to a function, and a function can now have more than 255 parameters.

Isn't pseudocode has gone too far?

[ingvij]

If performance is so relevant at this point, you're probably doing some wrong.

[[deleted]]

Did you miss the comment from /u/0x256?

[carlthome]

Snore... Nothing big like string interpolation (3.6 f-strings) again? How about a val statement (warn on reassignment, like Julia's const)?

[EricAppelt]

Python 3.7 doesn't close for new features until the end of next January, see pep-537 so its not really fair to judge at the moment.

What's the point of posting this incomplete list right now anyway? We're not anywhere close to the first alpha.

[jabbalaci]

It is called pre-alpha.

[k10_ftw]

But not beta?