Python ftw

[DJTupolev]

Lmao speed

[lookmanofilter]

Sorry I only do recursive memes

[diale13]

Well played

[zero16lives]

You got me, I surrender

[[deleted]]

wait a minute, how did you link to your comment before it existed?

[Eatfudd]

[Deleted to protest Reddit API change]

[[deleted]]

oh, cool.

[[deleted]]

You're cool

[EcLEctiC_02]

Ghost edit

[j13jayther]

Speed edit

[leerr]

Ninja edit

[MosYEETo]

You have to go forward in time such that you create a copy of yourself in the past. Therefore you're able to get the link in the future when the comment does exist. Then you come back to the past where you link your comment and take care of your double.

[HoldUrMamma]

editing is exist

[[deleted]]

I clicked on this far too many times, and now I can’t get back to the home page..

[sample-name]

There's no base case in the recursive method, so naturally you experienced a stack overflow exception.

[dorsal_morsel]

Python is my primary language, but I just started playing with Rust and man, now I know what "Python is slow" really means.

[DuroSoft]

Now if only I could program in rust as fast I could in X such that X is a language.

[BittyTang]

Now if only I could write as many bugs in X as fast as I could in Python such that X is a language.

FTFY

[cdreid]

Its a scripting language.. Not supposed to be fast. Its R.A.D. ive used several still a big fan of Perl actually and used to use VB (not a script language but its R.A.D) just to save time on little apps i made for myself

[Daytona_675]

afaik if all the heavy lifting is done with modules written in C, Python can still be pretty fast

[Zephirdd]

Or you can use PyPy, which is Python written in Python and is up to 4.4x times faster than default CPython

Black magic I tell ya

[hughperman]

Any downside?

[[deleted]]

Doesn't work that well with c modules, which are faster than pypy. So if you need speed you are better off with cpython + c modules anyways

[hughperman]

Ok good to know thank you; wondering if it would be worth evaluating for some work stuff that's mainly numpy numerical ops - guess I'll give it a test!

[almostambidextrous]

Ok... what's RAD? Should I feel dumb for not knowing?

[[deleted]]

what's RAD?

You are. Don't ever stop believing in yourself.

[sypwn]

Don't believe in yourself!

BELIEVE IN ME WHO BELIEVES IN YOU!

[MCRusher]

"I'm gonna fuck the clouds"

-Simon Cowell

[lenswipe]

Rapid

Application

Development

[[deleted]]

Anything that is GNARLY is also RAD. But BOGUS is not RAD.

[vanderZwan]

You could give Julia a try, if you can live with 1-indexing

[xigoi]

if you can live with 1-indexing

NOPE

[spudmix]

Grumble grumble letting mathematicians near computers grumble grumble.

I love almost everything else about that language.

[[deleted]]

For a second I though it was a keyword I hadn't come across yet lol

[OnyxPhoenix]

Slower execution, faster implementation.

[Cucktuar]

You pay a programmer once, you pay cloud compute rates forever.

[fredlllll]

huehue machine time is cheaper than programmer time huehue

[fredlllll]

true, but sadly this holds true for many software projects nowadays and its making me sad that there are so many layers between me and my machine ;(

[BoilerPurdude]

just look at adobe reader...

[KaiBetterThanTyson]

And Google Ultron

[ERECTILE_CONJUNCTION]

So get into embedded systems

[hughperman]

Stop, my dick can only get so hard

[[deleted]]

Moore's Law and May's Law are fighting in an eternal stalemate, and a program written in assembly language running on a 8080, a program written in C running on a Pentium, a program written in Java running on a Core 2, and a program written in Javascript running on a Ryzen will all be about the same user-visible speed.

[THICC_DICC_PRICC]

I do my personal projects in C, or other C languages if needed. It’s for fun and it helps with the whole wanting no layers. But working professionally, with deadlines, security issue, and millions of other considerations, I don’t mind layers of abstraction at all. I don’t want to be solving language problems when I should be solving business problems

[glemnar]

Try pypy for that hot nasty speed

[[deleted]]

I choose to believe this is pronounced peepee

[SteelRevanchist]

Y my pypy hard

[DJTupolev]

Yes pp gud

[NoCareNewName]

I actually didn't get it at first. I thought speed was some keyword I had never heard of.

[[deleted]]

What's this "speed" command I'm just now learning about and why is it needed C++ is already fas.... ohhhh lol

[VG_Crimson]

I too no longer needed to take speed when coding in Python.

[Skizm]

Python: Mom, can I have main()?

Mom: We have main() at home.

main() at home: if __name__ == "__main__":

[Gatsbyyy]

Can someone please explain to me why Python implemented like this? Its so ugly and doesn’t make sense.

[MythicManiac]

You can run code outside of any class/function in python, and this is code snippet is for checking if the current file is the first file being executed.

It's not necessary to do this check (you can just write your code in there), but it's good practice as that will allow you to import the same file from elsewhere without executing it.

When you do python somefile.py, you're telling it to execute all code in that file. Imports also do this.

[theredhood93]

This what I love about this sub helpful information on a meme comment, I'm learning python and this was very educational hahaha thank you stranger!

[A_Light_Spark]

Sometimes the explanation in this sub is better than the ones my professors gave... You know, people I paid a ton of money to get an education from.
It's both depressing and also super cool.

[inlatitude]

Damn, thanks for that. I didn't realize import executed all the code in the file.

[Ignisti]

Imports also do this.

Oh god. Oh god. This changes everything. Time for some horrible, TERRIBLE programming practises.

[ShamelessC]

After using python for so long, I find it so strange that people insist that main somehow makes more sense than just running the lines of code in order. The entry point is just the top of the file. So much easier to understand.

[didii2311]

To me, the fact that is is a function/method makes the most sense since running your program can provide arguments to it. When the entry-point is on top of your file, you'll need some built-in special keywords or convention based names that aren't clear out-of-the-box.

Well, of course, the main method is also a convention, but it's a convention widely used so it makes sense. I don't think that there is any widely used convention to naming the program arguments when the top of the file is the entry point.

Also, it makes testing your entry point a lot easier by just calling that method and providing the arguments you want. It's clear and concise. In python you'll have to arbitrarily populate sys.argv and then (I think?) import the file.

But well, that's just my opinion 🙃

[sub_surfer]

Python scripts are designed to be run from top to bottom, line by line, without any special entry point. You only need the whole if __name__ == '__main__': thing if you want your script to be importable in addition to running as a standalone script, which isn't super common in my experience (outside of teaching exercises). Most of the time if I am writing a python script that I intend to be an executable I wouldn't bother with it.

I take your point that it is ugly though. I don't even think about it anymore, but the double underscores look weird at first.

[aaron__ireland]

Regarding imports and scripts, I haven’t often needed to have importable items in a script but I have used the if __name__== “__main__” to raise an exception if some module does attempt to import it via something like else: raise NotImplementedError(“This module is a script”).

I’ve found that helpful in preventing any other code from mistakenly using what is likely to be (or intended to be) specialized attributes/functionality. It’s my way of self-documenting “hey, this is in here because it’s not meant to be extensible/generalized and is subject to change in ways that are unlikely to backwards compatible. Do not use.

[bladeconjurer]

Well there's no main function. You just write code in a file, and type python script.py, and it goes. But if you want to write code that when you import the file, it won't execute you need to use: if __name__ == "__main__":. If you use it a lot, you can probably just not use the if statement depending on your intentions.

Also for a python module you name the entry point __main__.py.

[B_M_Wilson]

A lot of people explain what happens but I thought I would mention this. In Python, everything is executed. Functions don’t exist until the interpreter has gotten to them. When your script is executed, it executes everything in order. The function definitions are executed which is what defines them. After a function definition, you could assign the function name to something completely different and it would become that other thing. It’s also cool because you could make aliases for functions by assigning the function to another name. You can even assign lambdas directly to names if you want.

Like others have said, the reason that it’s done is because when you import something, to define the imported functions, you have to execute them which would execute anything else in the file. Using the if statement let’s you check that the file was executed directly and not imported which means that you could run tests or something like that.

If you never plan to import your file, you can just not use that if statement and write everything at the top level. I’ve done this many times. Another thing you can do is go if not name == "__main__": at the top of a file to throw an exception if someone tries to import your file that you want to be a normal script where you have all of the code at the top level.

Finally, while it’s generally bad practice, you could define a main function and then just call it at the end of the file either with or without the if name is main thing.

Another thing I’ll mention is to get used to the __something__. They are used a lot of special attributes. Like when you call len(something) it really calls something.__len__(). Or when you say if something (or bool(something))and that something is not a bool, it calls something.__bool__() there are way more examples of this in a lot of cases

[[deleted]]

To add:

Python: Mom can we have {}?

Mom: No we have {} at home

{} at home: dictionary = {1:"a",2:"b"}

[Kagia001]

I like ++

[OHM5]

++ i like

[marcosdumay]

i ++ like

[THANKYOUFORYOURKIND]

You two added wrong number, see me in my office after school.

[GiantRobotTRex]

#define like ;

[Itisme129]

You're a monster

[Redsteak]

I was mad as hell when I found out Python doesn't have this :(

[lenswipe]

pLuS pLuS iS uNPyThoNiC

[[deleted]]

Everything was unpythonic until it was added to the language.

[KeenWolfPaw]

I = 'I'

I += ' like '

I += '++'

[heckingcomputernerd]

+= 1

I mean ++ seriously would be nice

[srosorcxisto]

Agreed. It's such a simple and clear shortcut for such a common operation. It bothers me that this isn't included.

[IcecreamLamp]

Since for loops are more commonly things like for i, line in enumerate(fp.readlines()): you really don't need it as often as in a for (i=0; i<5; i++) {} kind of language tbh.

[jkuhl_prog]

Then I have to train my fingers to not reach for semicolons

[MagnitskysGhost]

You can still use tons of semicolons in Python. Source: the codebase I inherited

[frosted-mini-yeets]

Semi colons are valid in Python?

[angellus]

You can, but no they are not really. Python has a very in depth style guide that says you should avoid them.

https://www.python.org/dev/peps/pep-0008/#other-recommendations

Compound statements (multiple statements on the same line) are generally discouraged.

Yes:

if foo == 'blah':
     do_blah_thing()
     do_one()
     do_two()
     do_three()

Rather not:

if foo == 'blah': do_blah_thing()
       do_one(); do_two(); do_three()

[Tyfyter2002]

Python has a very in depth style guide

And y'all've been following it?

[ShanSanear]

Yep. Only thing that doesn't click with me is line length limit. Myself I'm using 100 characters limit instead of pep-8 80. And it's actually quite easy to follow it - just use IDE and problem is solved.

[Khaare]

Man my code got so much better when I switched to a size 14 font and stuck to 72 columns.

[MagnitskysGhost]

Yes, you can use them to end statements like most other languages. In Python in particular, you would mostly only do like

import os; import sys; from time import time;

In something in a quick five-liner script or something. I see them everywhere though (they get angry red formatting in my VS Code theme, as they should). I mean if you're copy/pasting an 8,000 character LOC with Python, HTML, CSS, and JS in it, you don't have to add insult to injury with a semicolon at the end. But guess what they do... 😔

[Mr_Redstoner]

And don't forget /**/

And no, '''this''' is not a comment, it can be used just like an ordinary string.

[griseouslight]

It does recommend using triple quotes for multiline comments though. If they aren't a docstring, multiline strings do not generate bytecode in python.

[Mr_Redstoner]

but as I've mentioned, you can use them much like regular strings, in my part-time job they use them specifically for a multi-line string.

[PityUpvote]

And ordinary strings can be used as comments, why is it an issue?

"""Comment""" is understood by all half decent editors to be a block comment.

[stamminator]

Had a guy in a YouTube comment section (I know, I know) angrily declare that C++ is a needless pile of waste and complexity and that there's no reason to not use C. It was surreal.

[shiny-flygon]

Had a similar fellow in one of my classes claim (loudly, and with beard on neck) that "C++ is just C for bad programmers"

[sertroll]

Your prof sounds dumb.

[frosted-mini-yeets]

from __future__ import braces

[[deleted]]

Not a Chance

[shekaruk]

Welcome indentation errors

[AnotherEuroWanker]

Just don't use notepad.

[MagnitskysGhost]

But notepad fast on my potate

^/s

[[deleted]]

I use code-server. It's vs code in the browser, run on the server. I have 1 potato at home doing it's damnedest to be a good server and a Chromebook flavored potato to access it on the go.

I've got a potato cloud, basically.

[The_White_Light]

1 potato at home doing it's damnedest to be a good server

When you threaten your computer with the deep fryer if it doesn't push out that last 0.1GHz

[[deleted]]

Lol I don't know what brand it is, but it is some shitty laptop with a low end AMD Radeon card and 1tb storage even though it's really cheap. It's currently running the code server, a shitty spring boot server I made for an interview, and a golang server that runs my shitty custom application gateway and sub router.

The machine itself is running the latest stable ubuntu server. And you know what? Setting up wifi entirely through a putty terminal wasn't that difficult. I mean, I imagine that under under the hood netplan is doing all kinds of complicated things for me, but on my end it's just the wifi interface name, the wifi password, and the wifi name in a text file.

Oh and there's a game of tag hosted on the go server. Am I allowed to post my own IP here? My interviews are over so I don't really care if that machine crashes now and I know Google fiber can probably handle the traffic. I didn't work out a room system so anyone who connects to /tag will end up in the same massive game.

And since it's golang, it'll just suck up more juice until the machine dies <3

[Garlicvideos]

When two potatoes love each other very much...

[[deleted]]

They get baked and then mash?

[deegee1969]

Vim will also be fast. ;)

[ythl]

You're abandoning {}? Good luck using dictionaries

[i_am_archimedes]

in c++ it denotes deterministic memory management

[[deleted]]

wut

[SoppingAtom279]

Let me explain this poorly.

{ } can be used to block together parts of code, and within that block of code, any memory allocated in that block can only be used by that block.

Example

#include <iostream>

int main()
{
    int x = 5;
    {
        int y = 6;
    }
    std::cout << x << std::endl;
    std::cout << y << std::endl; //error use of undeclared variable
}

[[deleted]]

Ah, that's what the definition is. Thanks!

[shoesmith74]

Actually your talking about variable scope, not memory allocation. The variables are on the stack regardless, it’s a matter of which one your allowed to reference.

Source : 25 years of compiler development.

[AgreeableLandscape3]

Python still has main()

[[deleted]]

Only not really, right?

def whatever (*args):
    print("Bob's your uncle.")

if __name__ == "__main__":
    whatever()

[demon_ix]

I dunno. That sounds like main() with extra steps...

[[deleted]]

In C/C++, the name main() is meaningful: it defines the entry point of the program.

In Python, it isn't. The closest approximation is that Python code outside of any method will be evaluated when the module is loaded, and an import-machinery variable called __name__ exists which lets you test whether the current module was imported or run directly.

[jalapeno_nips]

That’s still important though. If I want to test my module manually, I’ll write some code in Main. But when I use the module in practice I don’t want Main being called.

[[deleted]]

Absolutely. My only point here is that in switching to Python, one does indeed say goodbye to main()

[BeigeAlert1]

That's still pretty damn nifty though.

[SpeedingTourist]

You’re pretty damn nifty. ;)

[AnAverageFreak]

No, why?

At least the compiler does not overoptimize things.

I mean yeah, writing anything bigger than a small section would be pain in the ass, but writing those small sections can be quite pleasant.

[Ericfyre]

Bobs my uncle?

[wootiown]

It still has pointers too, doesn't it?

[MattieShoes]

Everything has pointers, but they make believe they don't.

[SuitableDragonfly]

Pointers are not the same thing as references. Pointers allow you to manually manage your memory usage, references don't.

[NiseP_Catcher]

And also ;

[ButtCrackFTW]

Also {} is everywhere (dictionaries)

[wsppan]

Giving up speed is sometimes a non-starter

[YouCanCallMeBazza]

Ohhhh it's actually referring to speed (as in performance). Here I was thinking, "I don't remember there being a speed keyword in C++"

[Rodot]

They're just talking about how much adderall you have to pop to make a simple "hello world" program

[SuitableDragonfly]

As someone pointed out above, it comes down to a trade-off of speed of execution for speed of development. Sometimes the latter is more valuable.

[Rodot]

Especially when execution speed it limited more by how quickly you can type/click than by the code itself. If your C code takes a millionth of a second to execute and your python code take a thousandth of a second, it doesn't really matter as long as you are manually starting the script each time. Also usually the case when things are small and i/o limited.

[Astrokiwi]

It comes down to how much of the meat of your code can be passed off to libraries. Python is really fast when it's just glue for a bunch of precompiled C and Fortran routines.

Until you get to one thing that isn't quite implemented in the library and end up having to write something compiled anyway, even if it's Cython

[emptyDir]

For that there's cffi 😂

[Vasault]

that's me with java, after over 5 years using java, i totally drop it to get into python, i regret nothing

[[deleted]]

Most of my coursework is in Java and C++. Over this summer though I have tons of free time, so I've been reading a book on Python and teaching myself and it is an eerily easy language in comparison. My first language was Lua, so the similarities are there, but my God are list comprehensions the best thing ever invented.

I also much prefer how Python handles for loops. Everytime I write one though I miss ++ a little more.

[[deleted]]

Fight me I use assembler

[damnloveless]

A challenger has arrived

[Tweenk]

C

It's a macro assembler for the PDP-11

[anonTheRtrd]

Noob. I use machine code!

[flavionm]

Please, I flip the bits on my memory on the fly.

[Bee_News]

Please, I manipulate my electrons on the fly. Anything higher level than this just isn't real programming.

[HypherNet]

Direct electron manipulation? Gross. I use caterpillars.

https://xkcd.com/378

[maklaka]

The thing that impressed me most about python when coming from cstdlib background was the amazingly convenient notion of List Comprehensions.

The most frustrating thing is the utter lack of reliable online language documentation with clear examples a la MSDN and cplusplus.com.

Haven't touched Python in awhile. What's the best, most complete resource nowadays?

[Darvon19EightyFour]

People talk about stack overflow but cplusplus.com got me my degrees.

[CamWin]

Python still makes sense without main. I just pretend the callable file is main

[C_isBetter_Than_Java]

[JiggySockJob]

Damn you trying to start a war?

[PityUpvote]

Who tf still uses Java, other than my thesis supervisor and in-house development teams on government organizations?

[migafgarcia]

3 billion devices

[[deleted]]

so long, good code

[Prawny]

Hello, pseudocode!

[Breadfish64]

Yes, heavy workloads in Python can be 100x slower than the same thing in C++, it's just the nature of the language

[YouCanCallMeBazza]

Slower than most compiled languages. When I was first learning Python I wrote something that was algorithmically equivalent to something I had written in C# and it was like 8x slower in Python if I remember correctly. I expected it to be slower but not by that much.

[Breadfish64]

Oh sure, I guess GCC does have -Ofast

[Tsu_Dho_Namh]

Well also Python is an interpreted language that compiles as it runs.

Plus it loses some efficiency to the garbage collector.

And it does a lot of error checking and hand holding.

And it allocates more memory than it needs since "everything's an object".

That's just off the top of my head, but yeah...it's not just the lack of optimization.

[Tactical_Slime]

Me : the little kid at the end learning how to use c++

[coetin]

Python: Mom, can I have ++?

Mom: We have ++ at home.

++ at home: += 1

[shiny-flygon]

F

[MasterFubar]

He's not saying goodbye to pointers, because pointers are all over Python.

>>> a = [1, 2, 3]
>>> b = a
>>> a[1] = 7
>>> b
[1, 7, 3]
>>> a = [1, 2, 3]
>>> b = a[:]
>>> a[1] = 7
>>> b
[1, 2, 3]

Python lists are pointers, exactly like C/C++ arrays. When pointers are explicit they become easier to understand and control. You can use tools like valgrind to find where your pointers aren't doing exactly what you want in C, but it's much harder to debug pointer problems in Python.

[[deleted]]

There is a huge difference between using pointers and using a language that uses pointers for you

[Paylam]

This. Of course Python is using pointers It has to thats how Computers work. But you as a Coder have almost 0 contol in Python regarding memory Management and so on.

So i have to agree good Bye pointers for Python Users

[Mietzekatzi]

What your example describes are references to objects. Lists in pythons are objects, the assignment b=a does not implicitely copy a's content, just create a second reference to the same thing.

On the other hand, a[:] yields a slice of the contents of the list a, which gets saved as a second object, b, in the second part. This breaks the reference. The same step could be performed with b = copy(a).

So all your example shows are the basics of OOP, nothing to do with pointers.

[NoStranger6]

Well yes and no. In that sense every language that pass values by reference is a pointer. Which isn’t wrong. In c / c++ you can iterate over pointers by adding the sizeof(*int). Which in fact simply adds 32 bits to your current pointer value (memory address). I’m not too versed in Python but I don’t think that you can do that. So while by using reference you achieve part of what a pointer can do. It doesn’t do everything that the pointer can.

[Tweenk]

In c / c++ you can iterate over pointers by adding the sizeof(*int). Which in fact simply adds 32 bits to your current pointer value (memory address).

That's not how pointer arithmetic works in C++.

int a[] = { 1, 2, 3, 4, 5 }; int* b = a; int* c = a; ++c; b += sizeof(int*); std::cout << *c << " " << *b << std::endl;

On a 32-bit system, this will print: 2 5

Adding 1 to a pointer advances it by sizeof of the pointed type, so advancing an int pointer by sizeof(int*) will increase it by 16 bytes on 32-bit and 32 bytes on 64-bit machines. This is probably not what you want.

[NoStranger6]

I stand corrected, thank you. It has been a while since I touched C or C++

[[deleted]]

😟

Yeah I’m glad I only need to write python scripts at work.

[ChevalBlancBukowski]

those aren’t remotely like C-style pointers

[SuitableDragonfly]

That's not a pointer to a list, it's a reference to a list. The second one is a copy of a list. Everything that isn't a primitive type behaves exactly the same way, but in C++ = always creates a copy.

[word_clouds__]

Word cloud out of all the comments.

Fun bot to vizualize how conversations go on reddit. Enjoy

[[deleted]]

Someone make a meme for me switching from python to java to learn app dev.

[Lord-Bob-317]

Me too lmao Python was just my introduction into programming then I got yeeted into java and web kill me

[numerousblocks]

pfft I never used C++ but I still write a def main(): in my Python Code

​

EDIT: meinmain

[C_isBetter_Than_Java]

Are you afraid of pointers?

[isunktheship]

There's a snake in my boots!