Python's collections.abc | InvertibleDict

Learn your ABCs!

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CHAPTERS
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0:00 Intro
0:35 All the ABCs
2:28 Type hinting
4:03 Runtime Interface Checking
5:38 InvertibleDict
13:44 Outro

[tylerfusco]

It took me so long to understand covariance and contravariance of type variables, and honestly I would love to see you explain it, just so more people understand how powerful of a concept it really is

[problematque]

Excited for the 15 parts series j/k. Would love to see a discussion of covariance and contravariance for python, ty! Love #pycharm

[davea]

After surveying many python instruction channels on youtube I can confidently sayths is the best channel to learn about interesting facets of python programming. Your content should be sponsored by somebody like Khan Academy or LeetCode. I am baffled that you do not have more subscribers. Thank you for all of your efforts!

[PraecorLoth]

I've actually had a situations where an InvertibleDict would've been useful. And I'm glad typehints are optional. Great for when you're building something bigger or sharing code with others. But if I just want to get some data analysis code, it's great to not have to worry about all those intricacies. #pycharm

[felipedidio]

This channel has the best videos for serious programmers #pycharm

[knut-olaihelgesen]

Every time I see you have posted, I just know there will be a high quality video on an advanced topic. Love that.

[vidhanio]

Why would you use .register, even if you implement everything yourself? Is there any downside to inheriting and overriding everything?

[Jason-bt]

For the interfaces commonly used in Python, it is very convenient to use the abc module. But as far as I know most of the time you only need to use Protocol to type hint duck type custom classes. #pycharm

[SamuelDavenport-hv]

Your explanation of ABC's was very good, I didn't know you could register classes to be counted as instances of ABC's. That makes me interested in how that's accomplished under the hood. I look forward to your explanation of covarient and contravarient types. #pycharm

[lex_darlog_fun]

Actually, the part you omitted would be the most interesting to watch. I hope there will be a part 2 of this video.

[bolzenguido]

I recently came across the exact situation you describe and found it quite unsatisfying to manually define two dicts that are inverses of each other. This is very elegant, thanks a lot! #pycharm

[knut-olaihelgesen]

A video on the typing module and some advanced use cases? Like annotating a mixin class?

[matteolacki]

Hello, great video! One little thing: likely it would be more effivcient to cache the .inv method to avoid recreating the class each time one wants an inversely mapped element? Or am I missing something here? Best wishes!

[kalelsoffspring]

I've been programming for a while and only this month had a reason to look up what covariance is for typing, it's pretty neat but I definitely understand why you glossed over that :P In general I prefer interfaces to this direct inheritance as many languages only support one parent class, but as Python is Python I do appreciate what they offer with the ABCs

[PeterZaitcev]

In your implementation, the constructor always copies reference to the forward argument, even if backward isn't given. This can lead to the strange behavior when you create InversibleDict from other mapping and mutate one of them. Furthermore, if the original mapping was immutable, you'll get an error. I suppose #pycharm won't highlight that kind of error.

[chndrl]

Typehinting and strict data thpe restriction are something really useful for any level of collaboration of project.

[KappakIaus]

Great video: Nice summary of the basic concept, sprinkled with interesting sidenotes (e.g. i didnt know about the convention for hidden arguments)! Deliberately won't write the hashtag to avoid lowering the chance for people who would make better use of the license than me. 😊

[AntonioZL]

'Hey, kids! Today we're going to learn the ABC! That's right, little TImmy, Abstract Base Classed!!'

[yolosaurusrex]

thanks again for keeping up with the intermediate-advanced Python videos. much appreciated. #pycharm

[EvanBerkowitz]

People go crazy with type hinting. But seeing how #pycharm can use it to infer autocomplete suggestions is pretty slick!