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Advanced Python Features

blog.edward-li.com

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Re: Advanced Python Features

#71

Post by cl3misch »

pansa2 wrote: post #60
sakesun wrote: post #54

Earlier quoted context omitted.

It's more complex that decade ago, but still a relatively simple language. I can understand the article without much effort, while I scratch my head really hard when read about advance feature of Typescript or Scala.

> still a relatively simple language If only. I suspect very few Python programmers can even fully explain what `a + b` does. If `a` and `b` are instances of classes, many would say it's equivalent to `a.__add__(b)` or `type(a).__add__(a, b)`, but in fact it's much more complex.

Care to elaborate? Where is the complexity hidden?

Re: Advanced Python Features

#72

Post by lordgrenville »

djoldman wrote: post #69

This is wild and something I didn't know about: https://blog.edward-li.com/tech/advanced-python-features/#2-... def bar(a, /, b): ... # == ALLOWED == bar(1, 2) # All positional bar(1, b=2) # Half positional, half keyword # == NOT ALLOWED == bar(a=1, b=2) # Cannot use keyword for positional-only parameter

And you can use * for the reverse (every parameter from here on needs to be keyword-only).

https://docs.python.org/3.12/reference/compound_stmts.html#f...

Re: Advanced Python Features

#73

Post by HelloNurse »

TekMol wrote: post #2

TFA's use-case for for/else does not convince me: for server in servers: if server.check_availability(): primary_server = server break else: primary_server = backup_server deploy_application(primary_server) As it is shorter to do this: primary_server = backup_server for server in servers: if server.check_availability(): primary_server = server break deploy_application(primary_server)

The shorter version that saves the else: line assigns primary_server twice: it is OK for an assignment but a potential problem if doing something less trivial, and very ugly style in any case.

Re: Advanced Python Features

#74

Post by jsjohnst »

hk__2 wrote: post #29
porridgeraisin wrote: post #26

Earlier quoted context omitted.

I believe mypy infers i as an integer in i = 0. I remember I had to do i = 0.0 to make it accept i += someFloat later on. Or of course i:float = 0 but I preferred the former.

Yes, but not in arguments: def f(i=0) -> None: j = i + 1 k = 1 reveal_type(i) reveal_type(j) reveal_type(k) Output: Revealed type is "Any" Revealed type is "Any" Revealed type is "builtins.int"

Because it shouldn’t in function arguments. The one defining the function should be responsible enough to know what input they want and actually properly type it. Assuming an int or number type here is wrong (it could be optional int for example).

Re: Advanced Python Features

#76

Post by HelloNurse »

fxj wrote: post #10

This is all fun and games unless you have to debug someone elses code and they use a new feature that you didnt know about. Speaking for myself, I would be glad if there were a python_light version of the interpreter that has a simple syntax only like the early 3.x versions. just my 2 ct

You underestimate the social complexity of a simplified language. Everyone would disagree about the design (what is worth including because it is "simple" or necessary?), everyone would avoid using an handicapped language where features they need are gratuitously missing, and nobody would care about it enough to work on implementation and maintenance.

Re: Advanced Python Features

#77

Post by edwardjxli »

Hey yall! Original author of the blog here!

I did not expect to wake up at 4am seeing my post on front page HN, but here we are nevertheless :D

As the intro mentioned, these started off as 14 small tweets I wrote a month prior to starting my blog. When I finally got that set up, I just thought, "hey, I just spent the better part of two weeks writing these nifty Python tricks, might as well reuse them as a fun first post!"

That's why the flow might seem a little weird (as some pointed out, proxy properties are not really a Python "feature" in of itself). They were just whatever I found cool that day. I tried to find something more esoteric if it was a Friday, and something useful if it was a Monday. I was also kinda improving the entire series as it was going on, so that was also a factor.

Same goes with the title. These were just 14 feature I found interesting while writing Python both professionally and as a hobby. Some people mentioned these are not very "advanced" per se, and fair enough. I think I spent a total of 5 second thinking of a title. Oh well!

Re: Advanced Python Features

#78

Post by smjburton »

Some of these newer features don't seem like improvements to the language (e.g. the Walrus operator):

'''

# ===== Don't write this =====

response = get_user_input()

if response:

    print('You pressed:', response)
else:

    print('You pressed nothing')
# ===== Write this instead =====

if response := get_user_input():

    print('You pressed:', response)
else:

    print('You pressed nothing')
'''

The first implementation is immediately clear, even if you're not familiar with Python syntax. If you don't know what the ":=" operator does, the code becomes less readable, and code clarity is traded away in favor of being slightly more concise.

Re: Advanced Python Features

#79

Post by _l7dh »

edwardjxli wrote: post #77

Hey yall! Original author of the blog here! I did not expect to wake up at 4am seeing my post on front page HN, but here we are nevertheless :D As the intro mentioned, these started off as 14 small tweets I wrote a month prior to starting my blog. When I finally got that set up, I just thought, "hey, I just spent the better part of two weeks writing these nifty Python tricks, might as well reuse them as a fun first p…

Hey, I really enjoyed reading your post. It's straight to the point, the list is very rich and well illustrated with examples. I have been coding in python for the last 20 years and I nowadays rarely like reading these posts as much as I did for yours. Kudos.

Re: Advanced Python Features

#80

Post by hsbauauvhabzb »

edwardjxli wrote: post #77

Hey yall! Original author of the blog here! I did not expect to wake up at 4am seeing my post on front page HN, but here we are nevertheless :D As the intro mentioned, these started off as 14 small tweets I wrote a month prior to starting my blog. When I finally got that set up, I just thought, "hey, I just spent the better part of two weeks writing these nifty Python tricks, might as well reuse them as a fun first p…

I’ve coded python for 15 years and I’ve not seen many of these, so I’d consider them reasonably advanced personally.

One I think you missed is getters and setters on attributes!

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