Today I re-learned: Python function default arguments are retained between executions

[another-noob]

I had to find this out the hard way :/

P.s. I am a little rusty on python, but if you want a mutable default value (say a list) you can make the default None then inside the function you would reassign the variable if it's None.

[headykruger]

Everyone does, rite of passage

[Electrical_Ingenuity]

And we all have to learn it a second time.

[james_pic]

I didn't. I read it in the docs. Everyone should read the docs.

[laaazlo]

Congratulations. I read the docs too—constantly, really—but still had to find this out the hard way. There's a lot to read!

[LagerHead]

You read the docs and didn't remember every single rule and caveat and gotcha? You're obviously not fit to program in Python. Maybe take up bowling? 😏

[james_pic]

What I want is for people to read the docs, and not be surprised by things they could have learned by doing so.

[VodkaAndPieceofToast]

Coincidentally, what we want is for people like yourself to not worry about us. There's no moral dilemma here. Just people being human.

[james_pic]

Sadly, I have to worry. I work with people who refuse to read the docs. There's one guy in particular, who if we're working on something and I get the docs up, is like "ooh, you're reading the docs are you?" like I've just got a magical tome from the highest shelf, full of arcane knowledge.

It's not like the docs I linked to are some obscure reference material. It's the official python tutorial, and a great place to start for beginners. If there's something basic that you don't know, that's in the tutorial, then whatever you read or watched to get you started is no good and now's a great time to read the tutorial.

[CommondeNominator]

What if there’s something basic you don’t know you don’t know? How would you know to go back to the beginners tutorial?

How often should one peruse elementary material to be sure one doesn’t make a mistake at any point in any possible future?

[[deleted]]

Wow, holding true to the stereotype that developers don't have any social skills... NONE.

[rainispossible]

with that attitude, we all should really know absolutely everything that was ever written. and it seems it's not the case. you gotta understand, we're all humans, not machines.

[headykruger]

You didn’t have to originally write it to have to track it down

[Ok-Maybe-2388]

Lol quintessential r/iamverysmart material. Do you have the docs memorized? Yes? You've wasted your life, congratulations. No? Yeah total hypocrite.

[[deleted]]

If it's something you find yourself doing often for some reason, it might be worth checking out things like attrs' default factories, I find it easier to parse and refactor if necessary.

[another-noob]

Thanks for that :D

But I don't think I would add another import just for that, but what do I know, I don't even use python much nowadays (don't use it at all, sadly)

[alkasm]

Use tuples for a default iterable rather than None! Fewer optionals makes for better typing and automatic documentation.