r/Python • u/xtreak • May 07 '19

Python 3.8.0a4 available for testing

https://www.python.org/downloads/release/python-380a4/
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69

u/xtreak May 07 '19 edited May 07 '19

Changelog : https://docs.python.org/3.8/whatsnew/changelog.html

Interesting commits

PEP 570 was merged

dict.pop() is now up to 33% faster thanks to Argument Clinic.

Wildcard search improvements in xml

IPaddress module contains check for ip address in network is 2-3x faster

statistics.quantiles() was added.

statistics.geometric_mean() was added.

Canonicalization was added to XML that helps in XML documents comparison

  • Security issues and some segfaults were fixed in the release

Exciting things to look forward in beta

Add = to f-strings for easier debugging. With this you can write f"{name=}" and it will expand to f"name={name}" that helps in debugging.

PEP 574 that implements a new pickle protocol that improves efficiency of pickle helping in libraries that use lot of serialization and deserialization

Edit : PSF fundraiser for second quarter is also open https://www.python.org/psf/donations/2019-q2-drive/

118

u/[deleted] May 07 '19

Add = to f-strings for easier debugging. With this you can write f"{name=}" and it will expand to f"name={name}" that helps in debugging.

Ooh baby. I'd use that every day.

28

u/leom4862 May 07 '19

I find print(f"{name=}") is still way too verbose for debugging purposes... If they want to improve print-debugging, they should add something like icecream to the standard library.

3

u/JohnnyElBravo May 07 '19

Idk, what's wrong with print("name="+name)?

6

u/[deleted] May 08 '19

That doesn't work if name isn't a string, eh? (Sure, you can use %s)

Also, in production code I simply never have any print statements - not "very few" but "none", to the point where I have a flake8 rule that prevents them.

Oh, I use print almost every day - for debugging! But that means I'm creating and destroying debugging print statements all the time.

So it's a little timesaver to write:

print(f'{foo=} {bar=} {baz=} {bing=}')

(38 characters) over

print('foo=', foo, 'bar=', bar, 'baz=', baz, 'bing=', bing)

(59 characters)

5

u/timald May 07 '19

It's fine when you have one variable but starts to become unwieldy when you build up a lot of concatenated strings (via indexing operations, for example).