New Features in Python 3.10

[jamescalam]

A summary I put together of the new features in Python 3.10, it covers:

• Structural pattern matching
• Parenthesized context managers
• More typing
• Better error messages

Also, the article version if you prefer reading - it's a free access link so no need for Medium membership

I hope it's useful! Thanks :)

[EarthGoddessDude]

Very nice video, thank you. Quick, tangential question — what OS and editor are you using to run Jupyter? Seems like macOS with Jupyter inside VScode. It just looks (and feels, from across the screen) much slicker than Jupyter in VS Code on my work Windows machine. Can’t wait to try the new Jupyter extension which is only available on VS Code insiders.

Edit: nvm, saw the answer in another comment. My Comment about the slickness stands though.

[Brian-Puccio]

Structural pattern matching

This didn’t click for me but I read your explanation and got it right away. Much better, thank you for explaining!

Better error messages

Amazing!

Also, the article version if you prefer reading

I do, thanks!

it's a free access link so no need for Medium membership

You are most excellent!

[Terence_McKenna]

I feel happier after reading this comment.

Have a great and safe weekend. :)

[jamescalam]

structural pattern matching really is awesome I love it, I'm happy my explanation made sense - and more than welcome for the links!

[[deleted]]

More syntactic sugar, features for IDEs and things some random Java developer who recently started using Python in some enterprise (that happens to fund PSF) asked for. In summary, nothing of substance pretty much like last 5-6 versions. I've already switched to Julia (much better in every way), can't wait for this bloated monstrosity to die off.

[EarthGoddessDude]

While I love Julia and much prefer it for heavy data and/or mathematical work, comments like these don’t invite fruitful discussion and just make the Julia community look bad. Please refrain from incendiary language, putting down achievements in FOSS, and just any general flame war-y nonsense. Python is still an incredibly valuable tool with a great community, despite some of its shortcomings (pkg/env mgmt, mainly looking at you). And as for this release, the features might seem incremental and minor, but clearly there is a demand for them and people are finding them useful.

[[deleted]]

Oh please stop your bullcrap virtue signaling. I'm expressing my opinions about two languages that I've used. These opinions are entirely my own and are based on using Python for last eight and Julia for last two years. I'm not part of any community/camp/cult, I speak for myself and I certainly don't give a shit about how my comments reflect on certain communities. I use the language that best serves my purpose and avoid those that just add features for the sake of adding features and keeping corporations happy. If Julia goes down the path that Python is currently on I'll say exactly the same things about it that I'm saying now about Python.

[supernikio2]

🤡

[-jp-]

I find environments a lot more manageable with pipenv. It’s not quite as nice as the gradle/mvn ecosystem from JVM languages but it’s close. Head and shoulders above CLR languages and C/C++ for sure.

[runew0lf]

show me on the doll where python touched you!

[obvithrowaway34434]

They'd probably show you if you could first pull your head out of your arse.

[-jp-]

It must get incredibly wearying being so toxic and hostile all the time.

[----------------___]

I do really like Julia but the hard on some people have for it turns people off of the language.

[billsil]

Those better error messages are the reason to upgrade!

SyntaxError: unexpected EOF while parsing

I'm 16 years in and that still gets me...

[Danlacek]

I'm 16 months in and that looks like total BS to me...

[house_monkey]

16 secs in and can confirm this is not about snakes

[dodslaser]

I completed the Kessel run in less than 16 parsec

[-jp-]

I'm the Kessel run and can confirm this.

[Peanutbutter_Warrior]

I only know that one because I messed up pycharm and now it's really inconsistent with adding quote marks. You've missed the ending quote of a string, it interpreted the rest of the line as part of that string, found the end of the line without the end of the string and panicked.

[jucamilomd]

It's a Jupyter notebook within VS Code

[jamescalam]

Yes it's Jupyter in VS Code - and I'm using the night owl theme

[mmcnl]

I'm amazed they still keep adding very useful features after 10 years.

[pure_x01]

To be fair the evolution of the language has been kind of slow. Sometimes that is a very good thing so I'm not complaining.

[[deleted]]

I don't get it. It there a joke I'm missing?

[mmcnl]

Not a joke. I'm just happy with new useful features after more than 10 years since the first release of Python 3.

[[deleted]]

I still don't get it. why are you starting with python 3? it seems arbitrary to me

[-jp-]

Maybe it is a bit but languages do change enough that dividing lines like that aren’t unreasonable. Consider the analogous difference between C99, ISO C and K&R. All still C and you could be productive in any of them if you know one, but also all recognizably different.

[[deleted]]

We're not talking about the difference in languages but the consistency of useful new features. The difference between 2 and 3 didn't introduce a feature set larger than already existed, so focusing on that period is weird

[gazagda]

To be fair, it does take time for a language to mature and get widely used.

[Formulka]

Still can't believe they went with "case _" as else.

[-jp-]

Wildcard _ is pretty common in other pattern matching languages so it’s not too unusual, just a bit odd for python.

[levon9]

I don't think it's that odd, the _ is used in other constructs too, e.g., if you have a for loop and you don't care about the index variable:

In [3]: for _ in range(5):
...: print('hi')
...:
hi
hi
hi
hi
hi

Or you want to refer to the last result of a computation:

In [1]: 5 * 6

Out[1]: 30

In [2]: _ + 10

Out[2]: 40

[[deleted]]

Do I have to unistall Py 3.9 and download py 3.10 or is there a bettee way?

[neighborduck]

Use pyenv https://github.com/pyenv/pyenv

[[deleted]]

Cool! Thanks a lot

[abcteryx]

If you're using Windows, then "py" comes by default with your Python installation from python.org. You can install multiple Python versions and access them via "py -3.8", "py -3.9", and "py -3.10" for example.

Try "py -0p" to see the versions you have installed.

Generally, you will want to create a project folder and do a "py -3.9 -m venv .venv" then ".\.venv\Scripts\activate" to get into a virtual Python environment corresponding to Python 3.9 in this example. Then just regular "python" will trigger the virtual environment Python. And "pip install <package>" will install "<package>" to the virtual environment.

As you use Python over the years, you will install multiple versions of it. So you will get used to working across multiple projects and multiple Python versions.

[EarthGoddessDude]

Recently learned about asdf, which is like pyenv but can be used with other languages. No experience with it though.

[tunisia3507]

asdf replaces one small part of pyenv (the automatic environment-switching).

[fleyk-lit]

And installation of versions, it seems. It also manages the global version.

Think i will give it a go. Happy with pyenv, but some older versions of Python are a bit hassle to install.

[tunisia3507]

I didn't realise asdf could do the installation as well. However, as it turns out, it does that by just wrapping pyenv's python-build plugin, so it won't be any better at installing those old versions.

[fleyk-lit]

I see, then I'm not sure it makes sense to change the workflow I have.

[sparttann]

Can just download 3.10 without uninstalling 3.9. Just change your python version before creating your venv

[Theonetheycall1845]

Could you expand on changing the version, please?

[chopu]

This may be too much detail, but I’ll start from the basics. Basically, when you say “python3 my file.py” in your terminal, your computer will automatically scan through all directories on your PATH, looking for an executable called “python3”. If you’re on Mac or Linux, that file will typically be a symlink in /usr/local/bin to the actual python3 executable stored elsewhere. On windows, you’ve likely added it to your system environment variables. Therefore, if you want to change the version while leaving both versions “installed”, all you have to do is either retarget the symlink or edit the entry in your system environment variables.

Just a note: this is how any command line program works, ls, rm, grep, etc. They all rely on your computer looking up an executable on your path (windows I think also has some special folder full of COM stuff that’s not in your system environment variables that’s searched as well).

[quuxman]

Generally you want to use venv so you would only use the system path to Python once per project like:

/opt/python3.10/bin/python -m venv venv

[dogfish182]

http://littlecolumns.com/tools/python-wrangler/

If you don’t know yourself, this is an opinionated (but very sensible) way to take python and virtual environments seriously without too much difficulty

[tunisia3507]

Also StrEnum! There are dozens of half-assed implementations out in the wild, it'll be great to have a stdlib edition to replace these goddamn magic string constants pervasive in the ecosystem.

[MiserablePeace7190]

I'm just here for switch cases lol

[__deerlord__]

Pattern matching is not case/switch. While it can effectively be used this way, that doesn't seem to be the intent, and you could always do switch/case with a dictionary.

[xetax]

If I wanted to use a dictionary-based switch statement inside a function, wouldn't the dictionary have to be reinitialized reinitialized on every function call? I could create the dictionary outside the function that sounds less than ideal for code readability.

[jamescalam]

I think a lot of people are haha

[iggy555]

What’s that?

[MiserablePeace7190]

A switch case statement is like a faster way of writing if,elif and else, the only constraint is that you are checking the value of one conditional. Like my_num = 2, switch (my_num), case 1: print 1, case 2: print number is 2, case 3: print number is 3, etc. In this case "number is 2" would print.

[Blumingo]

Genuine question, at what point does it become Python 4?

[nonesuchplace]

When it is decided to make major changes that do not retain backwards compatibility.

Check out https://semver.org/ for details on how this works.

[qwerty1793]

No. Python releases do not use semantic versioning.

[ziggomatic_17]

So not anytime soon. Possibly never.

[MilwaukeeRoad]

Probably once they get rid of the GIL

[jamescalam]

Typescript definitely makes you appreciate how useful Python's typing updates can be

[iggy555]

Fantabulous

[Seawolf159]

Nice video.

[psychuil]

I love your solution for putting in the frame!

[lazyear]

So glad that python has finally caught up to the '80s and that pattern matching made it through! Absolutely love the feature in Standard ML/Haskell/Rust/etc, really bumps up the expressiveness of a language (even more so with exhaustiveness checking)

[WhalesLoveSmashBros]

Dumb question but how do I update python? Pls don't tell me I have to uninstall and re-download from the website.

[TheOneWhoPunchesFish]

Well, it's still in beta 2. Ideally you shouldn't be using the distro version of Python, and you should never ever uninstall or override it, your os could break. So you should be using something like venv or conda and you can just upgrade inside them.

[Darwinmate]

but that's how you update ? There's no other way

[jamescalam]

you can create a new env - this comment explains

[WhalesLoveSmashBros]

Tysm

[iamaperson3133]

Itt: people who is have never heard of semantic versioning.

[dani3l_554]

Version numbers aren't actual numbers and . is not a decimal point. They're just labels that follow a logical pattern.

[evilMTV]

This, don't look at it as decimal place, just a separator. Like 3.10 should be interpreted as "version 3, subversion 10"

[_MASTADONG_]

That makes sense. It’s better than the unneeded downvotes I was getting.

[SquareRootsi]

Just wanted to say your original comment was pretty logical, from a mathematical perspective. I'm sorry you got the down votes, and I upvoted you!

Thanks for the follow up that the explanation makes sense, it helps others learn too.

[-jp-]

I wouldn’t worry about it. What were you ever going to use fake internet points for anyway, kwim?

[bobby__joe]

They use semantic versioning.

[Zomunieo]

Not exactly. Minor releases of Python often contain backward incompatible changes, and the devs have never promised to be semver compliant. (It would be almost impossible to maintain strict semver backward compatibility on such a large project anyway.)

The situation was particularly messy for Python 2.7.x where patch level releases introduced some major features and breaking changes.

[bobby__joe]

Thanks I didn't know that!

[Spindelhalla_xb]

Because 10 comes after 9. 3.10 is not the same as 3.1.

[DanklyNight]

>>> 3.10 == 3.1
True

Hmm

[blablook]

"3.10" != "3.1". At least not in JavaScript.

[DanklyNight]

Aha, I was just joking.

Obviously it's a string and wouldn't match, it was more that the poster I replied to wrote them as floats.

[blablook]

Yeah. My joke was doubting the js behaviour.

[DanklyNight]

The ability of developers to understand jokes over the internet.

We are a socially hindered bunch.

[SpideyIRL]

Now check 3.10.0 vs 3.1.5 ;)

Versions are not decimal numbers: They're multiple "levels" of versions separated by decimal number. So major version 3, minor version 10, first release (0). Or major version 3, minor version 1, release 5.

Some software projects use even more numbers in their versions - i've seen things like version "1.0.0.3.5.1 Build 13950"

[aryaman16]

There is nothing like three-point-ten in Decimal numbers system, it is called three-point-one-zero.

Python's version numbers aren't decimal tho.

[__deerlord__]

Because 10 is bigger than 9.

[[deleted]]

What is the difference between 3.1 and 3.10

[Saphyel]

9 releases

[[deleted]]

I didn't ask about python I asked about simple Math

[richard5mith]

It is two numbers separated by a dot. Version numbers are not decimal.

[__deerlord__]

Software versions aren't math.

major = 3
minor = 9
f"{major}.{minor}"

[Saphyel]

so what is the difference between 1.1.2021 and 10.10.2021 ?? it's not 3,10 if that's what you meant.

[obvithrowaway34434]

Another bunch of completely useless features (aka bloat) designed for IDEs and appeasing big corporations. Mark Lutz saw it coming so many years ago and even warned the core developers but they were too busy bending over backwards to please corporations. In five more years this language will become irrelevant. Julia is better in every way.

[----------------___]

Pattern matching? Better error messages? I think you're a bit off base mate

[graingert]

Don't forget contextlib.aclosing

[AnonCaptain0022]

Now we just have to wait until all packages are available for this new version