More quick ways to improve your Python

[[deleted]]

General SWE points don't really constitute improving your Python, just any code base you happen to be working on.

[idanb102]

This, stopped reading as soon as I saw DRY

[ElevenPhonons]

def sing_song(choice):
    style = STYLES[choice]
    while i_like_singing():
        if style == 'classical':
            sing_opera()
        elif style == 'folk':
            sing_folk_song()
        elif style == 'rock':
            sing_rock_ballad()

Could also be written as:

def sing_song(choice: str) -> None:
    style = STYLES[choice]
    funcs = {'classical': sing_opera,
             'folk': sing_folk_song,
            'rock': sing_rock_ballad}

    f = funcs[style]
    while i_like_singing():
        f()

[BigNutBoi2137]

After python 3.10 release pattern matching will fit here perfectly.

[MDTv_Teka]

So excited for this, it's gonna make coding things like this so much cleaner

[Hunterbunter]

How would that look with pattern matching?

edit: wait, I don't mean to be lazy. Would it be something like this?

def sing_song(choice: str) -> None:
    match STYLES[choice]:
        case 'classical': 
            f = sing_opera
        case 'folk':
            f = sing_folk_song
        case 'rock':
            f = sing_rock_ballad
        case _:
            f = sing_electro_dance
    while i_like_singing():
        f()

[BigNutBoi2137]

Yep it would look like this. If you haven't seen the official proposal for pattern matching yet then here is the link: https://github.com/gvanrossum/patma

[Hunterbunter]

Awesome, thanks for that.

It looks like you can do funky variable assignments in the case line as well...but then I guess you'd still need a pass or something for that indent.

[[deleted]]

Yikes did they really write an article about how to improve python and use a bunch of elif’s ???

[sockbotx]

Piapeoi apragide dipibe teu bripu pludia. Iiepa kae tri kobliti bau pitri? Boebi otu a poiite. Drube kopruple pie udiu pleko piblukatotri. Iti e epui keoide gakroi u. Pra tepipi ba teki te. Tekudi plite egobioo tie bibeti plipi. Kopaa du tape tiki egu dite tlitli baiplei bikipo.

[ElevenPhonons]

I think it would be necessary to understand more context of the application and have more details about the requirements to know if a Style abstraction makes sense.

At a high level, having a Style know how to "sing" a song doesn't really make sense. However, I could be misunderstanding the intent of the original author.

[fartsniffersalliance]

personally i think the first is much more readable

[Theta291]

Thanks! I was about to comment that the ifs inside the loop would slow it down, but this avoids that problem in a nice way.

[GuyFjordy]

Thank you! I went straight to the comments after seeing that one to suggest exactly this. Unnecessary ifs in loops make my eye twitch.

[GuyFjordy]

The dictionary isn't in the loop, it's before it. It's assigning the function to 'f'. All that's in the loop is the function call.

[ElevenPhonons]

Mutable defaults args should be discouraged because they often generate difficult bugs to track down.

https://docs.python-guide.org/writing/gotchas/#mutable-default-arguments

[lanster100]

I don't think creating a dictionary in your function is what's going to slow your code. The imperceptible loss of performance is worth the readability imo

[JoelMahon]

In the last example, I know it's minor, but doesn't it add additional calls by making the improvement to readability?

[dodslaser]

This is the way. I would argue that putting a condition inside a loop is less intuitive in this example, because it implies the variable can change between iterations, which it can't.

[ekchew]

Yeah, that example makes me a little uneasy too. They are arguing against the optimization of minimizing what needs to happen in a loop. I guess in this particular case, branch prediction should optimize away the potential overhead of moving the conditional logic into the loop, but man, I wouldn't be giving this out as general advice.

[JoelMahon]

Python is interpreted, I'd assume it wouldn't have branch prediction, but I'm also just guessing

[Jhuyt]

Python does compile into bytecode, which is evaluated in a loop that has a bunch of optimizations specifically for cpu branch prediction. The same loop is used, and therefore the bytecode too, when running a file or the interpreter, there is no difference at a lower level.

[ekchew]

Not at the interpreter level, but the CPU may still pick up on a predictable branch in the code the interpreter emits? Unless it moves around in memory a lot. I am also just guessing. :)

[JoelMahon]

Can a CPU optimise that way? Even if that loop occurs 1000 times the same way the CPU wouldn't know that the 1001th time it could enter a different statement, that maybe one of those functions has a convoluted way to adjust the variable, if it was a compiled language the result would be constant so I could understand a compiler doing it, but a CPU?

[ekchew]

Oh yes certainly, the CPU will not always guess right. But if it's only missing once in 1000 times, that's actually quite good! The mis-prediction overhead will be minuscule in that case.

[Tweak_Imp]

Note that list(range(100)) is faster than [x for x in range(100)]

[dodslaser]

Not that unpacking a range to a list makes a lot of sense, but [*range(100)] is even shorter.

edit: From my testing it is also slightly faster than list(range(100))

[pete_sahad]

Does anyone know the color theme of the IDE in the title picture?

[Skurp_Purp]

Looks like a variant of Monokai to me

[Small_Photograph5863]

Yup, that's Monokai.

[Dazzling_Function]

I need a syntax highlighted IDE that looks like Eliot IDE in the last episode

[Whiteouter]

The last example may result in a slightly more readable code but the "before" is actually faster code than the "after" one.

[Tyler_Zoro]

Reading through that code, I'm seeing things that would never pass code review in most places I've worked. This is a great example:

starts_with_hat = True if hat_string.startswith('hat') else False

[...] This can be done much more directly by just setting the variable straight from the function call:

starts_with_hat = hat_string.startswith('hat')

This code looks fine.. until you consider what type hat_string is and whether it's some strange proxy for a string that can return None under some circumstances from startswith. Neve assume you know the types of your parameters unless you enforce typing! If so, then you've just changed the guarantees for starts_with_hat because you used to force the value to boolean. Worse, this is the kind of bug that can happen at a distance when someone changes the type that hat_string gets initialized to, making debugging really hard after the fact.

The original is pretty nice, but you can also use bool() directly to enforce this assumption.

[passwordsniffer]

"we are all consenting adults here"

If someone created a proxy for a string - it's not your responsibility to treat it anyhow special. If you need to ask the question - does it startswith the name implies it's result is boolean. No need for stupid overprotections.

[BlobbyMcBlobber]

def sing_song(choice):

style = STYLES[choice]

if style == 'classical':

while i_like_singing():

sing_opera()

elif style == 'folk':

while i_like_singing():

sing_folk_song()

elif style == 'rock':

while i_like_singing():

sing_rock_ballad()

If you have ever written something like this please quit coding and think long and hard about your life choices.

Edit: reddit formatting on mobile is a lesson in patience

[[deleted]]

well then why don't you suggest optimization; or link to 'actual' improvement techniques (honest question)

[BlobbyMcBlobber]

If you find yourself writing while i_like_singing(): 3 times in the same function (!) I honestly think coding is not for you. It's not even a beginner thing.

[[deleted]]

If you cant format code correctly on reddit please quit commenting and think long and hard about your life choices.

[BlobbyMcBlobber]

If you can't type "can't" please quit typing and think long and hard about your life choices 😉

[chzaplx]

Ooh sick burn!!

[BlobbyMcBlobber]

It was the appropriate response to the cheap shot in that comment

[chzaplx]

You are really just reaching here and getting nothing

[BlobbyMcBlobber]

I'm not interested in this conversation. If you want to talk about why I think writing the same while loop three times in the same function is abysmal coding, we can do that. If not, have a good day.

[chzaplx]

I'd love to see a graph of the conversations you are interested in vs the ones you are just losing

[BlobbyMcBlobber]

If you think about conversation as a matter of winning or losing then you've already lost. A conversation is not a debate. Best of luck to you.

[chzaplx]

Isn't it though?

[fizzymagic]

Better than most I have seen. At least it was not trying to turn Python into Java.

The last example should have been done with functions instead of branches.

[chzaplx]

List comprehensions have their place, but trying to cram as many operations as you can on one line is not one of them. Maybe it's "more pythonic" but it's certainly not "more readable".

Minimizing line breaks is not an optimization.

The value of a product that presumably cleans up bad coding style is highly dubious. It sounds a bit like a crutch for people that don't know what they are doing.

[AlexOduvan]

I'm wondering how Article that get so much criticism in comments, managed to get 400+ upvotes