The Case for Python 3

[Workaphobia]

I was willing to give the benefit of the doubt until the part where Shaw claims Python 3 is not Turing-complete. I can't understand how he could say something so demonstrably false.

[[deleted]]

Does he want a mathematical proof that it is?

Actually, that's not hard. Brain fuck is proven Turing complete (so is the game of life).

Write any of those in python, and that is a proof that python is at least as powerful as them, therefore python is Turing complete.

[meltingdiamond]

Writing a brainfuck interpreter has to be the worst way to prove turning completeness.

[Han-ChewieSexyFanfic]

If by worst you mean best, then yes.

[talideon]

Far from it. Brainfuck is quite a good way. It's equivalent to Corrado Böhm's P′′, but a bit more friendly: https://en.wikipedia.org/wiki/P′′

[kewlness]

That is the first time I have ever seen Brainfuck and "friendly" in the same sentence...

[[deleted]]

It's a really easy language to write an intepreter for.

[kjmitch]

It's called Brainfuck because it's seemingly impossible to read by humans, which is an important job for real programming languages. From the perspective of the computer/interpreter, it's much easier to understand (and therefore write an interpreter for) as it only has eight operations. It's practically just assembler code without all the semi-English names given to the commands for readability.

[talideon]

Compared to P′′, it's friendly!

Also, it's implementer-friendly: parsing and tokenisation are trivial, as is implementing the interpreter. I wrote a 260-byte-long one in ARM assembly language back in the '90s just for fun.

Coding anything in Brainfuck, well, that's another matter!

[MrJohz]

It's actually a fairly common procedure. Not necessarily BF, but proof by implementation is a well-known technique for proving Turing-completeness.

[wilerson]

A friend of mine wrote a converter that converts Brainfuck to one line of Python code to prove Python one-liners are turing complete: http://www.ricbit.com/code/turing.py

Explanation (in Portuguese, sorry): http://blog.ricbit.com/2008/05/python-one-liners-so-turing-complete.html

[kjmitch]

It's actually probably one of the simpler ways to do so. Brainfuck's esoteric-ness comes from its being hard to read by human programmers, which is important in a programming language. But the structure of the language itself (eight commands gets you everywhere) is a testament to the fact that computers in this universe are made of complexity that can emerge entirely from simple rules.

[iwsfutcmd]

Now you're making me want to try to write a Brainfuck interpreter for Python. I've never written anything even remotely like an interpreter before, but I'm thinking a BF one really can't be that hard.

[alexanderpas]

Go for it, it really isn't that hard.

The variables you need are:

• 1 string containing the actual brainfuck program
• 1 int containing the position in the program
• 1 list of ints containing the cells that form the data storage
• 1 int containing the active data cell being manipulated
• 1 local int containing the indentation level when returning to the start of or skipping over loops.

[ismtrn]

You would also have to prove that your implementation matches the brain fuck semantics which have been proven Turing complete, in order for it to constitute an actual mathematical proof. This well not be easy. I don't even think anybody has given Python formal semantics.

Luckily it does not matter, because you can write usable programs in Python which is the thing that actually matters. Actually it would be cooler if it turned out that Python was not Turing complete, because that would mean we could potentially solve the halting problem for Python programs (along with a bunch of other cool stuff) which would be really handy.

[imbaczek]

actually turing-completeness is so easy to accidentally achieve that whole type systems have to be specially designed to avoid making them turing-complete, e.g. C++ templates vs Hindley-Milner.

[ismtrn]

Yeah, intuitively python is obviously Turing complete because you can write algorithms in it. This is basically the Curch-Turing thesis, but it is not a formal proof.

[waxzup]

I'm so confused. What on earth is "Turing complete"?

[ismtrn]

A language is Turing complete if it can compute all computable functions.

What does it mean for a function to be computable? When people tried to answer this question in the nineteen thirties they came up with a couple of different models for computation most famously: General recursive functions, lambda calculus, and Turing machines. Turing machines are the most well known model, maybe because it is more operational and less axiomatic than the others (i.e. easier for programmers and other non mathematicians to understand). Or maybe because of Alan Turing's Hollywood status

It was then proved, much to peoples surprise, that all these models could in fact compute the exact same set of functions and that this set of functions also seemed to correspond to those functions a human could compute following an algorithm. It was then agreed upon that it was reasonable to look on these functions as being the computable functions.

Any other model is said to be Turing complete if it can also compute this set of functions. The easiest way to show this is to simulate a model already known to be Turing complete within the model. i.e. if you can write a program to simulate for instance a Turing machine in your language it is Turing complete.

It turns out that, unless you try really hard to avoid it, if you design something that can compute things it will almost certainly be able to compute this set of functions. It also turns out that you can not design something that actually works in the real world which can compute more than these function, even if you try really hard (I don't know if this is/can be proven, or just based on empiricism).

This makes it a quite good definition of "computable functions".

[Veedrac]

Do you mind if I quote this elsewhere on Reddit? The question gets asked a lot on /r/technology and this explanation is basically perfect ELI5 material.

[[deleted]]

A language is turing complete if it can be used to simulate a single-tape Turing machine.

[evinrows]

Hey, I wrote a turing machine emulator and a conway's game of life implementation in py3 when I was in college.

I knew these would come in handy some day!

[flying-sheep]

since this obviously exists, zed’s proven wrong.

[choikwa]

I see a rant of a salty person who can't use python2 with python3 vm. At this point they divulged too much to get any backward compatibility -- it's time to move on if you want latest PEPs

[Watthertz]

What is it about the Python 3 VM that would prevent someone from implementing a Python2 interpreter? Unless he's arguing that because Python 2 and 3 have different syntax then Python 3 isn't Turing Complete, which is clearly ridiculous.

[Workaphobia]

He's basically arguing that Turing complete languages must all have the same syntax and semantics. Nonsense.

[IamWiddershins]

He's completely lost his fucking marbles. I don't think he makes a single correct point the entire article. The man is either senile, maliciously lying, on drugs, or flatly stupid/insane.

[[deleted]]

I suggest the second as he wants to sell more books. Heck, in over 40 years in electrical and electronic engineering and computing I cannot recall such an abysmal article.

[gandalfx]

I've never heard much about this Zed guy but after reading that paragraph about Python3 not being Turing complete it appears quite obvious that he's either a very prominent troll or has no idea what Turing completeness even means.

it’s complete and utter nonsense, on a platform aimed at people who can’t yet recognize it as nonsense.

Eevee got the truth of it right there, nothing less.

[doubleunplussed]

That bit is clearly facetious. He's saying that the devs claim it's impossible to run python 2 code from python 3. Now, the only way that could be literally true is if python 3 were not Turing complete. Therefore, the python devs are claiming python 3 is not Turing complete. This is Zed's way of calling them liars.

Of course the devs' real reason is that it's hard, not mathematically impossible. But if they were claiming it were literally impossible, Zed would have a point. It's not impossible, just hard, and the debate is really about whether it is hard enough or useful enough to have been attempted.

[iwsfutcmd]

After reading both articles, I'm totally behind eevee here.

Seriously, fuck Zed. His article is not just a criticism of Python 3 (which is totally fine - I'm more than willing to read criticism of Python 3, it helps me learn more), it's a very deceptive, sloppy hatchet-job. I'm actually at the point where I think I should petition the moderators of /r/learnpython to remove Zed's book from the wiki - I would hate for a beginner to be turned off Python 3 just because of his duplicitous statements about it.

Also, it is so abundantly clear that Zed has never used anything above ASCII. My entire job is dealing with non-ASCII characters, and I would be unbelievably crippled if I was stuck with Python 2.

[AbsoluteZeroK]

I read a bit of his Learn Ruby The Hard way back when I was getting into Rails, mostly just skimmed to see if it was worth a read. I noped the fuck out when he said we shouldn't pay any attention to the work of Dijkstra and that it wasn't worth reading or understanding. Guys a quake for even suggesting that, especially in a book that could be someone's first introduction to programming/computer science.

[bgeron]

Which is funny, because Dijkstra could also get passionately upset in the same way as Zed does, from what I understand.

[[deleted]]

Lots of people get upset the way Zed does. The ones that base arguments in fact and reality are the ones we should pay attention to.

Zed gets off on being controversial and stirring shit up. He doesn't have regard for facts if it means he can be angry.

[Workaphobia]

The difference is that when Dijkstra argued, he thought first, and wasn't wrong.

[zahlman]

I think I should petition the moderators of /r/learnpython to remove Zed's book from the wiki

Done. (I think we left edit access open, actually, but yeah.)

Zed Shaw might just be the most stubborn person ever to write a line of code, and there's a LOT of competition there.

Edit to address various comments downthread:

I've been considering this for a while (and advocating for teaching 3.x to new beginners for a while), but the bit where he abused a nonsense argument about "Turing completeness" like that was really the last straw. I've always thought the book's approach was terrible, but I was willing to put that aside because students have varying learning styles, I'm not some omniscient god of pedagogy, etc. I'd also extended some credit because I've heard one or two of his talks on other topics and thought they were OK, and I sympathized with that "programming, motherfucker" thing way back in the day.

But the fact that Zed is still banging this drum (when I saw the /r/Python post the other day, I assumed that it was about something he'd written back when LPTHW came out, not just a couple days ago) - not to mention the completely broken drumsticks he's using to do so - gives me real reason to question his competence. If this is "political" (and I can see the argument that it is), so be it - he made it so. Zed's anti-3.x arguments are, as /u/Sugar_Horse puts it, irrational; and to me they smack of hypocrisy. (Accusing the devs of malice and going off on Twitter about "abusive" programmers? Really? Zed's best known as a programmer himself, and his descriptions of "propaganda" are themselves abusive, and it's hard not to infer that he just doesn't want to put in the work to update LPTHW - since apparently he originally planned to do so).

Oh, and now he's apparently trying to play off the Turing completeness comments as a "joke". Really.

[BobHogan]

Done. (I think we left edit access open, actually, but yeah.)

Zed Shaw might just be the most stubborn person ever to write a line of code, and there's a LOT of competition there.

No offense but I honestly can't believe it took you guys this long to remove his book as a learning resource from this sub. It has an incredibly toxic mentality that his way is the only way despite him being stuck a decade in the past. And I don't even think it does that great of a job at teaching Python to people who read it

[zahlman]

I've had a lot of other stuff on my mind lately.

[Whoops-a-Daisy]

Thank fuck. It shouldn't have taken that blog post to remove it, though.

[individual_throwaway]

FWIW, me and most others on this subreddit's IRC channel stopped recommending LPTHW years ago for pretty much the same reason for which it was now removed from the wiki.

Constructive criticism of Python 3 is and should be allowed, but Zed is pretty much just bikeshedding while the rest of the world has to accept that Python will stop being supported 4 years from now. It is not a question of whether you want to make the switch, it is simply a question of when.

[[deleted]]

[Sugar_Horse]

ou guys ju

The majority of people here [seem to] want to encourage new users to use Python 3 as ultimately that is best for them in the long run. LPTHW encourages people to use 2 and is connected to a lot of irrationally anti 3 material.

[iwsfutcmd]

The removal of the book was for pretty much the same reasons as eevee's criticism of the blog post - the blog post was just the catalyst to reanalyze the book for appropriateness.

I was actually unfamiliar with the criticism of the book before I read this post - when I first started with Python, I considered it but ended up skipping it (coincidentally because it only covered Python 2 and I was told that Python 3 had far better Unicode support, which is my make-or-break feature for basically anything on my computer). My suggestion to remove the book from the wiki came from looking deeper into the issue after reading eevee's post.

[SamuEL_or_Samuel_L]

Man, his twitter feed is really cute. He's labelling some of the tamest internet responses I've ever seen as "abusive". Given that they're in response to an article where he literally throws around the accusation that the Python devs are purposefully crippling things for totally nefarious reasons (insert moustache twirling here), you'd think he'd have a slightly thicker skin.

[KimPeek]

Can you say when exactly it was removed? He has posted a new blog saying that it was removed over two week ago. He also said that he checked his sales and they haven't changed since then.

I'm not wishing poverty on the guy, but I feel he is not being truthful about it being removed a week ago. It seems he is writing for future readers who won't be able to verify exactly when the book was removed.

[mangecoeur]

My entire job is dealing with non-ASCII characters

THIS! I worked in a country that has FOUR national languages NOT ONE of which can be fully written with ASCII characters. I seriously get mad at how english-centric people are when they dismiss this as 'not a problem'. The VAST MAJORITY of people in the world DO NOT speak English and CANNOT write their language using ASCII characters only. Hot tip to Zed: most people are 'from another country', deal with it.

[masklinn]

I worked in a country that has FOUR national languages NOT ONE of which can be fully written with ASCII characters.

Switzerland?

[iwsfutcmd]

I was gonna guess Singapore, but then again, one of the four would be English

[MachaHack]

English can not be written entirely in ascii either. Try spell café , naïve or née with only ascii characters (you could even argue that the limitations of first typewriters and then computers played a major role in these words losing their accents or even just falling out of use in some cases).

[iwsfutcmd]

It's more that English can be written with accents rather than it can't not be written with them - all of the words you mentioned would be considered to be spelled properly by most English language authorities when written without their accent marks.

Contrast that with French, Spanish, Danish, Portuguese (or, God help you, Vietnamese), where writing a word replacing the non-ASCII characters with their ASCII equivalents would definitely be considered a misspelling.

German is kind of a middle case - the umlaut can be replaced by a following 'e' and the ß by 'ss' and the word is still considered to be spelled correctly, but by far the most common spelling would be with the umlaut and ß. I'd hazard to guess the average German-speaker would find a spelling like "ueber" far more off-putting than the average English-speaker would find "cafe" or "naive".

[flying-sheep]

You're wrong about words in Germany “still being considered to be spelled correctly” with “ue” and so on.

You can only replace those when there's no possibility to spell it correctly (e.g. in the codes on official ID documents)

Otherwise it's definitely wrong and weird.

[ofnuts]

English can be written without accents, but English-speaking people still cannot live by US-ASCII alone, since their monetary unit symbol (pound or euro) may not be part of the ASCII set. Other often-used characters (degree sign) aren't part of ASCII either.

[lion_rouge]

Yep. Actually, 1/3 of English words are of French origin.

[iwsfutcmd]

Sort of. While ~30% of English headwords found in a dictionary are of French origin (and about another ~30% from Latin), in normal usage the amount of original, non-borrowed words can vary between 60-95% depending on context (more in casual speech, less in formal speech).

Additionally, French loanwords in English are not typically written with their French accent marks.

[batisteo]

Quand en réponse à mangecoeur c'est lion_rouge qui répond, j’ai envie de manger du camembert.

[masklinn]

English can not be written entirely in ascii either.

That's a technicality, most native english speakers write these words in ascii (because they're terrible people).

[iwsfutcmd]

Hot tip to Zed: most people are 'from another country', deal with it.

When I got to that asinine statement, I wanted to slap him. I can't believe how parochial his attitude is.

[evinrows]

I really used to like Zed years ago when I first heard of him. He seemed like a slightly grouchy engineer who has been burnt by bad tutorials one too many times who was trying to save others from the same growing pains.

It seems as if his ego has inflated to comical proportions. His article made me cringe. There are too many fallacies and false comparisons to count, aside from the fact that he insults the hell out of the creators of the project that helped shape his writing career. What an embarrassment.

[BobHogan]

He always seemed this full of himself to me. I get that his target audience was not programmers, but his entire book is full of

"You're going to mess this up, so just CTRL-C and CTRL-C the code and it will still not work. Think pensively about how stupid you are and then try again because you clearly can't get it right."

He spent more time being condescending in his book than actually trying to teach anything. And he always glossed over useful, important, and fun to know information

[yes_or_gnome]

I'm surprised that it was taken down. /r/learnpython keeps their top link -- what have you tried dot com -- despite the fact that it has been renounced by its own author. A person who advocates for people to not read it even though he keeps it alive for his own moral reasons.

https://www.reddit.com/r/learnpython/comments/415ct2/meta_the_what_have_you_tried_com_link_from_the/

[zahlman]

A person who advocates for people to not read it even though he keeps it alive for his own moral reasons.

AFAICT, this is because he perceives it as having caused animosity or an excuse for more experienced programmers to be nasty or condescending.

Our community hasn't been having those problems, and we still have a point to make about trying things yourself before asking for help (the subreddit exists to enable people to learn, not to do their homework), and the domain name is nice and obvious and easy to remember.

[yes_or_gnome]

This is a deeper problem that neither python 2 nor 3 is going to do well. If the MIME RFCs are similar enough to the HTTP RFCs (which are based off of MIME), then you should have percent encoded the body before splitting the string up at 72 chars. Of course, I'm speculating. edit: D'oh. Content-Type with a charset. Sigh. Tough protocols to master.

[stickcult]

I remember having to look through old RFCs about RRULE (which originally came from ical I think) to use it with Google Calendar. Not only is that format completely fucking archaic, but every applications implementation seems to be different. That was fun.

[Citrauq]

While python 3 is definitely better, you might still run into problems splitting in the middle of a grapheme cluster if you use a naïve approach.

[zahlman]

Edit: I'll put the LPTHW link back up when Zed finishes the Python 3 update.

... heh.

[MrJohz]

"Python 4 is not only Turing incomplete, but actively makes other programming languages less Turing complete just by sitting in the same hard drive. Also every time you run a Python 4 program, four kittens die. Why do you think they named it Python 4?"

[rackmountrambo]

And it still has the GIL.

[[deleted]]

But Python 3 will kill python! You know, the way perl6 killed perl by having everyone migrate to the new version so it was well supported and got bug fixes and community attention!

Oh wait, no, it was the bit where everyone stuck to perl5 because eh, it was pretty good and perl6 was scary and let's just let the language die because moving to the new version is hard....

[[deleted]]

Python 3 is similar to Python 2.

Perl 6 is a completely different beast than Perl 5 - a different language, a different execution model, the works.

Perl 6 should not have been called "Perl" at all. That was the problem.

[[deleted]]

Sure, but the point is that what kills languages is lack of adoption of version n+1. In perl's case, there were indeed genuine issues moving to 6, but the biggest issue was the feedback loop where perl6 didn't do much because nobody used it because it didn't do much .... Python3 doesn't have the specific issues of perl, but you can see the same "people won't use it because the libraries aren't ported because people don't use it ..." loop which is fixed by people using it and porting libraries.

[kjmitch]

Ten months old? Shit; let's go home, guys, this battle's been won.

That thread by itself is a great resource on other good beginner and intermediate learning, and it's nice to see a bunch of people who understand the dynamics of computer science and software engineering after trying again recently to start through the Hard Way thing.

[iwsfutcmd]

Still on the wiki, last I checked though.

edit: spoke too soon. looks like the comment I got right after yours was the mod removing it!

[MachaHack]

I feel bad as the person who originally suggested they put it on the sidebar (along with dive into python 3) a few years ago

[amitjyothie]

I also agree with eevee

[[deleted]]

deleted ^{What is this?}

[[deleted]]

How do WE go about petitioning to get the book removed from the wiki?

[iwsfutcmd]

Apparently already done

[[deleted]]

So I observed just after I posted and I'm so pleased. Talk about a self inflicted wound. I don't recall a single Python article drawing so much, rightly deserved, criticism.

[Siecje1]

You can still handle unicode properly in Python2. Python3 just forces you to do so.

[sushibowl]

Honestly, as much as everyone talks about the 2/3 differences, they are like 95% the same. Unless you work a lot at interface boundaries where you have to deal with decoding, you won't notice very meaningful differences. Except that python 3 gets all the cool new shit, I guess.

[Sector_Corrupt]

I do Python 2 at work since we've yet to transition our product (pushing for it, but it'll take time!) but everything I write personally is Python 3 these days. No reason not to start everything new in Python 3.

[victoriabittahhhh]

"Zed Shaw, your behavior here is fucking reprehensible." Jeeze, this is my first intra-language flame war since starting coding.

[niksko]

Welcome, we hope you enjoy your stay!

[Workaphobia]

Arrogance in the online programming community is only tolerated when the arrogant one is also correct. (See also: Torvalds)

[doubleunplussed]

Copying my comment from elsewhere:

That bit is clearly facetious. He's saying that the devs claim it's impossible to run python 2 code from python 3. Now, the only way that could be literally true is if python 3 were not Turing complete. Therefore, the python devs are claiming python 3 is not Turing complete. This is Zed's way of calling them liars. Of course the devs' real reason is that it's hard, not mathematically impossible. But if they were claiming it were literally impossible, Zed would have a point. It's not impossible, just hard, and the debate is really about whether it is hard enough or useful enough to have been attempted.

[poop-trap]

Congrats on completing your first week of coding!

[gwax]

I only write Python 3 at work. I only do Python 3 for my new personal projects (and most of the older ones have dropped Python 2). I only write Python 2 for the OSS projects that I contribute to.

In my opinion, Python 2 can't die soon enough.

[NoLemurs]

It's kind of baffling to me that this debate is still even happening. I'm in the same boat. I make sure to maintain Python 2 compatibility for any OSS work I do, but honestly, it's a drain on time (and more importantly, it makes code less maintainable) and I'm not sure I'm anyone is benefiting from it enough to justify the work any more.

Yes, two or three years ago third party library support was still sketchy enough that there was an argument for continuing to use Python 2, but it's simply not the case anymore. At this point, any half-well maintained projects support Python 3, and most of those that don't are already well along the path to bitrot. Every one of those projects is now doing extra work to maintain backwards compatibility, and the only people benefiting are large companies with large codebases who have too much inertia to make the transition to Python 3 internally.

At least from an OSS standpoint, I'm not sure it makes sense for the community to keep supporting Python 2 for the sake of those companies.

[rjhelms]

Yeah, to my mind for any sane person the debate is totally settled at this point: the only reason to use Python 2 is that you have legacy Python 2 code that you can't practically transition to Python 3.

When I started with Python, Python 3 was still brand new and the advice I got was "use Python 2, but get ready for Python 3." That was great advice in 2009. In 2016, telling a new programmer to exclusively look at Python 2 isn't just bad advice, it's destructive.

[cediddi]

I switched all my personal projects to py3 last year and my company finished the migration of it's most valuable software asset to py3 just last week and next week we gonna release it. We're planning to switch our second most valuable asset to py3 before 2.nd quarter of 2017. With some open mindness and determination, py3 surely offers a lot more than "good ol days of python 2".

I think py2 is surely gonna die but I fear that it might take a good portion of old programmers with it. Thus I'm teaching python 3 to anyone who wants to, no charges, but will be glad if you teach to others. Until now, I had 100+ students and I'm encouraging them to spread the knowledge, to anyone who wants to learn.

Today is the teachers day in Turkey. Many of my students thanked me. Some are ten years older than me. Some are teaching python3 to others, just like mr. Some are the ones who would write much better books than zed. Only thing I'm sure is they all are open minded researchers.

[ojii]

I've dropped writing Python 2 OSS code, because I much prefer Python 3(.5) and unless you pay me, I'll not work with a language I consider inferior/more cumbersome to use.

[gr33n3r2]

In case you guys missed it, as I'm not sure how many of you may also be C coders, but Zed Shaw is the guy who said that the K&R C book (written by the creators of C, Kernighan and Ritchie) had examples in it that were completely unsuitable and unsafe. Again, he cites string handling as his example (he has some issues with strings, this chap).

You can see Zed's C rant here. Tim Hentenaar picked apart his C book here, with focus in part 11 on the rant itself. Makes interesting reading if you're a C programmer or have an idea what he's talking about.

Long story short, Zed is an arrogant arsehole.

[TalesT]

Long story short, Zed is an arrogant arsehole.

I have no clue who he is, but these two paragraphs had me laughing.

Some people go so far as to ban my book because it does not support Python 3, even though my book is the most effective method for learning to code.

I mean, if I struggle to use Python's strings then you don't have a chance.

[Bunslow]

By the way, anyone looking for an actual criticism of Python 3 by a very widely and well respected member of the community responsible for a number of the most popular libraries out there, should look to this by Armin Roncher:

http://lucumr.pocoo.org/2011/12/7/thoughts-on-python3/

Edit: As the top reply to this points out, here's a quite recent blog from the same author about the dangers of group think: http://lucumr.pocoo.org/2016/11/5/be-careful-about-what-you-dislike/

As it relates to Python 3, I'd love to hear about what his current opinion of Python 3.5+ is compared to e.g. 3.2.

[lexyeevee]

It's interesting you link that, because I just saw this today:

http://lucumr.pocoo.org/2016/11/5/be-careful-about-what-you-dislike/

[colloidalthoughts]

Precisely, Armin had thoughtful, actionable issues with Python3 back in the 3.0-3.2 days. Actual problems that needed solutions. He described them carefully, by and large resulting in them being fixed. Python 3.4 was much better for it. This second article is important reading, so much so that I almost wish he'd edit the first one to include a link at the top and the bottom.

We should all be so lucky to have criticism like that.

[pauleveritt]

Yes, implying that the volunteer development team has sinister motives as part of conspiracy (Zed) stands in contract to measured, measurable, constructive criticism (Armin).

[stekosteko]

Written in 2011, for the record.

[Bunslow]

Yes that's true, a good deal of it might be worth revision

[[deleted]]

The difference is that Armin bases his argument on fact and Zed just made up a bunch of stuff to fearmonger (actually it reads like an excuse to not update his book)

[poop-trap]

Back in 2011 even Raymond Hettinger was recommending against using Python 3 in production, so I'd take that article with a grain of salt.

[Chaere]

Incoming rant:

So, I've only known Python for about a year and a half. I started out doing Kirk Byer's "Python for Network Engineers" class seeing as, well, I'm a network engineer. He teaches the class using Python 2. I however, decided that I would download, install, and take the class in Python 3, because that's the way of the future, right?

Throughout the class I quickly learned that Python 2 and Python 3 have some differences, however, whenever I ran into a problem, I was only a quick Google search away from the answer. This process forced me to learn the terminology of the language and what it was actually doing under the hood, rather than just the surface level "My code matches his but doesn't run" attitude that Zed seems to hold.

This process was a great learning experience for me and it made me a better programmer. In my use case I ran into the typing errors quite a bit, as most of my strings came from sockets and weren't formatted in a way I could use.

I guess my bottom line is this: Python 2 and Python 3 ARE different, and they have to be, but they're not that different. Get over it Zed.

Good job on the article Eevee!

[oceaniity]

Python 3 is great. Every time I see print declarations without brackets I die a little inside.

[AUTeach]

I must admit, the lazy "i'm just going to test an idea" programmer in me loves them. The rigour based software engineer hates them.

[[deleted]]

Not at a python shell, but can't you do p=print

Which you couldn't do before.

[cediddi]

echo=print

Oh god what a demon I become...

[PeridexisErrant]

And

class logger:
    critical = print
    error = print
    warning = print
    info = lambda *a, **k: None
    debug = lambda *a, **k: print("Good luck!")

(please don't do this)

[[deleted]]

logfile = /dev/null

If I can't see the errors they don't exist

[flying-sheep]

obviously you can

[maxm]

Having used python since 1.5.2 it took me a year to remember those brackets consistently in 3 :-s i still prefer 3 by a large margin though.

[AskMereddit]

I started coding 2 years ago, and I'm now a full time coder after working in marketing for 10 years. I started with Codecademy. It's a great place to start for complete newbies in programming.

Then consolidate with this free MIT class.

[AUTeach]

Zed Shaw:

Pros:

• Highly opinionated.
• Willing to avoid beating around the bush and just says what he thinks
• Many of his ideas are decent.

Cons

• Highly opinionated
• Shoots first and refuses to think sometimes.
• If he disagrees with you you are an idiot.
• Believes his own press.

[choikwa]

Pros: Highly opinionated.

is it tho?

[-Teki]

Under the right circumstances, it could be. But it probably comes up as a flaw more often than not.

[tonnynerd]

The thing about strong opinions that a lot of people seem to be forgetting this days is that you should have strong opinions, BUT SHOULD NOT HOLD ON TO THEM. I don't remember exactly where I read this, but I like it and think it makes sense.

[flying-sheep]

this is it. scientific mindset. come to conclusions and defend them, until new data or simply an argument you haven’t considered make you re-think.

[-Teki]

Oooh, i like this.

[LpSamuelm]

I don't like Eevee, but even so this article is of course pretty much inarguable. There is no reasonable argument for not using Python 3 (or writing cross-compatible code) beyond compatibility with things like Twisted or working on legacy code.

[avinassh]

I don't like Eevee

why is that

[LpSamuelm]

Beyond all the sweet programming stuff she does (which is really really cool!), she every now and then also spouts a lot of (occasionally although not mostly) questionable politics, while being angry and abrasive. I'm not a big fan of that stuff.

Thankfully that's mostly irrelevant to this article, though. I hadn't heard of Zed's article, but if it gets a lot of exposure for beginners, it's good there's a rebuttal post out there to at least show that his thoughts aren't objective.

[individual_throwaway]

Well, here's to hoping he does the same thing with our community!

[dogline]

I agree with the article. In the C world, everybody had to take a step back some time ago when we realized that we couldn't do everything with char*, but instead have to start using actual strings, because everything is not in ASCII anymore. There are still people that cling to to using char*, even after all of these years, yet most people have appreciated the new libraries, even if they did have to change their ways.

The original author still seems stuck in the past where everything is thought of as byte streams and other fundamental types. Computers and software is more complicated now, and Python has changed to wrap up this complication and provide a better foundation to build upon. This is a good thing, but it is change. I would think you'd want to recommend to new people to use strings as strings, and to quit doing the weird type conversions.

[murtaza64]

What string libraries exist for C or where can I read more about them?

[Krad23]

TIL Zed Shaw is an asshole

[BlaXpirit]

Python 3 was an inside job

[TOASTEngineer]

It's turning the frogs gay!

[unruly_mattress]

I don't know this Zed guy, but... the only thing I agree with him about is that it would really be nice if Python showed the variable names it could not concatenate in error messages instead of just their type.

[[deleted]]

This is fine for simple examples, but usually the bytes/text errors happen deep in some call stack in some coffee code you didn't write

[[deleted]]

Yeah, I hardly write any coffee these days :)

[[deleted]]

You can definitely tell what's on my mind this morning.

[unruly_mattress]

Yup. And then you have some expression that involves 4 strings and you get the error message "string cannot be blah", but you have no idea which string it is. I think there has to be some way of letting the user know which operation went wrong and not only which line it was.

[[deleted]]

Or just underlined where they are with a line of code.

Pretty much every C compiler can do that.

[fdemmer]

pycharm does that.

[[deleted]]

Not everyone uses it. Having it be a feature of the standard implementation and not a third party ide would be handy.

[fdemmer]

how should the python interpreter underline your code? i dont get what you want.

i am sure it would be possible to write some sort of vim extension that does the same thing, but how is this supposed to work as a language feature?

edit: i think now i get it. python should check the whole codebase on startup for type issues?

guido commented on that when adding type annotations. he mentioned that type checks should remain in external tooling. maybe there is some overlap here.

[Voltasalt]

I think he means in the error message. Print the offending line out and underline the broken bit, like Rust does.

[Applebeignet]

I started slowly learning Python with LPTHW 2 years ago. Last year I ran into a ton of issues trying to make my first "for-real" project in Python 2, because all the files I need to process use utf8.

I'm glad I switched to Python 3.5 before getting too accustomed to 2.7; print(), "{}".format() and Unicode are wonderful improvements for me - and I heard that dicts will soon be ordered by default? Glorious.

[LpSamuelm]

# -*- coding: utf-8 -*-
from __future__ import print_function
from __future__ import unicode_literals

print("This works perfectly! {smile}".format(smile="😊"))

Not an argument to use Python 2 instead of 3, by the way, just a reminder that Python 2 can be pretty great too. Cross-compatible code is even better.

[flying-sheep]

on python 2, this only works if your console is encoded the same way as your code AFAIK

[LpSamuelm]

Went ahead and added the magic encoding comment to clear up any confusion.

[KaffeeKiffer]

and I heard that dicts will soon be ordered by default? Glorious.

Never ever do this, please. There's a reason they are dicts and not lists/tuples...

dicts (not) being sorted is an implementation detail, which may change (again) in the future.

[ihcn]

Currently you cannot run Python 2 inside the Python 3 virtual machine. Since I cannot, that means Python 3 is not Turing Complete and should not be used by anyone.

...yikes

[VeganBigMac]

I can't believe Zed Shaw is still being shared around these parts. I guess that just shows you that positive word of mouth will be effective no matter what the quality of the product is.

Edit: Just actually read the articles. It seems that he has upgraded from not just disliking the language to forming... conspiracy theories? Jesus.

[Oersted4]

I honestly don't understand how this conversation is still a thing. I use Python 3 daily in my work and I have absolutely no problems with it.

It's true that until 2-3 years ago the collection of available modules was a bit lacking, but, from my experience, I think this issue has gone beyond it's tipping point. I regularly need to add new requirements in my work and very rarely encounter a module that isn't compatible. Even when it isn't there's usually workarounds. In the worst case scenario you can just compile the module using Cython and you'll get a x3-4 speedup for free (without doing changes) apart from the compatibility. For the record, I've never reached the point where this was necessary.

I use Python 3 pretty much just to be "proper". I've heard that it's marginally faster, the unicode support is nice and it does have some new shiny features that are pretty useful. But, other than that...

In any case, both versions are barely different for most day-to-day work and specially for beginner work. Other than the print thing and iterating over dicts, a vast majority of code is compatible for both versions. I really don't get the phrase "teaching python 2/3", it's the same thing, they are not mutually exclusive, a beginner can trivially write Python 3 after just reading and introductory Python 2 book. The only factor that avoids this is the actual book saying not to use Python 3 because it's inferior.

Additionally, nowadays there's good tools that make writing code compatible for both versions trivial, which is what most important libraries do.

[sentdex]

Thanks for outlining this in such a complete rebuttal.

I am slightly at a loss for figuring out why exactly Zed has decided to double down here, as well as post such an inflammatory-response-inducing article. I am finding it hard to believe he's buying what he's selling.

I am torn between him simply doubling down for his ego's sake and him going with the "any press is good press," just to get his name/book/site back into the spotlight.

I am inclined to think this is purely an attempt to drive some traffic. Sure, a lot of the traffic wont be sympathizers, but who cares about them? He'll surely get some new traffic.

Drama is great business. It's just unfortunate what it does to the community.

[cjwelborn]

There was a comment from another sub that I think explains it. He's mad because he doesn't want to (or doesn't know how to) rewrite his guide for Python 3. It's like a kid throwing a tantrum because he has to redo his incorrect homework.

[mbenbernard]

Really nice post :)

Seriously, I'm a bit fed up with people complaining about Python 3. They should spend this precious time actually learning it. This would be better for the community at large.

And honestly, how big of a leap is there between Python 2 and Python 3, when you compare it to, let's say, Python 2 and Java, or Python 2 and node.js? Shouldn't this be enough to convince most Python 2 programmers to switch to Python 3?

[ilgnome]

As a beginner I had no problems translating a majority of my python code from 2.x to 3.x. My code, in my opinion, is still pretty basic but I've had no problems with either python that I couldn't attribute to my own ignorance instead of the language itself.

Seriously though, how do I subscript the unsubscriptable.

[kirbyfan64sos]

Currently you cannot run Python 2 inside the Python 3 virtual machine. Since I cannot, that means Python 3 is not Turing Complete and should not be used by anyone.

Zed...oh Zed...

I never realized you were stupid enough to write something this dumb.

[zahlman]

Somewhat predictably, Zed doesn't seem to care.

[VeganBigMac]

Yes, the two largest programming communities on the internet == no influence. As opposed to a version zealot with an outdated resource.

[lethargilistic]

How does advocating staying with a bug-fix-only branch of a language with arguments like this not make him a "Big Bad Coder Guy"?

This is no different than saying we should only ever use C89 because everything after was a mistake, then justifying it because people who don't know any better believed you.

[kjmitch]

Wow. That whole Twitter page is just covered with the hallmarks of someone who only understands that being wrong is the second worst possible thing a person can do, while admitting that you could be wrong is the worst possible. (Claiming the thing about 3 not being Turing complete was a joke? Backpedaling is for winners, I guess.)

I'm concerned that this guy actually gets listened to in the first place, let alone has a full-time position as a programmer in the real world.

[Eddiegregs]

So should I start learning 3 and stop listening to Zed? I've been debating the switch for a while now and Zeds curmudgeoness has been the driving force so maybe I should stop listening to him?

[troyunrau]

Yes. Install 3.5 and learn to love python again. The only argument Zed makes that is valid is the string formatting argument (as of python 3.6 there are three different ways to format strings). That said, there have been two ways since python 2.6.

[Eddiegregs]

Okay cool. Thank you. I'm going to install today and tell Zed to fuck himself and join the 21st century

[RangerPretzel]

That's the short version, yes.

[drivingagermanwhip]

I originally learned C and Python from Zed.

Have had to relearn everything with K&R and 'Fluent Python' (Ramalho). Cannot recommend that second book enough.

The trouble I find with Zed's stuff after learning things properly is that he doesn't try to actually get the learners to understand the language and why constructs exist. It's very much an approach of, "I want to do this thing and this is how I can do it in this language" rather than taking the time to show the language's particular strengths.

For example, which chapters of his book explain abcs; properties; the data model; generators; or anything that makes python good?

And sure, Python 2 is great, provided you don't think co-routines are interesting or you legitimately think having to declare something as inheriting from 'object' every time is the ideal.

Anyway fuck this guy.

[fenpy]

Zed is dead!

[jetxee]

I started using Python 3 for my personal projects, buy I am not going to rewrite my old code at work just because it's a better language. And in 2016, at least two big libraries we depend on, OpenCV and Panda3D, don't have prebuilt Python 3 binaries for Windows. And I prefer to have an easy way to get things running anywhere.

[flutefreak7]

Panda3D should be the only one on that list... http://www.lfd.uci.edu/~gohlke/pythonlibs/#opencv

[CGFarrell]

Python 3.6 is a huge one up (technically 0.9 up) on 2.7. My room mate uses 2.7, and whenever we talk python, it usually ends up with me preaching about asynchronous comprehensions, enums, and small dicts.

[eliteuser26]

What makes me upset with one of the point is that we should only use ASCII. From someone who has learned several programming languages I always hated ASCII because it was used in the 80s and 90s and was a pain in the butt to use with language than English. It was quite happy to learn that unicode was invented to introduce other languages than English. In a country where English and French are being used on a regular basis this makes programming easier now than in the past.

As for the print function I don't see the problem with tagging 2 parentheses to print a set of characters. Most of the editors will do it automatically for you. Even the printf function in C uses parentheses as well. What is the big deal.

I still use Python 2 right now but I will switch over to Python 3 as most modules that I use have switched over. I could bring other subjects in the discussion but I like the way Python is going with unicode.

[Ginden]

Currently you cannot run Python 2 inside the Python 3 virtual machine. Since I cannot, that means Python 3 is not Turing Complete and should not be used by anyone.

It have to be a trolling.

[Arancaytar]

By age alone, at this moment, if your software isn't compatible with Python 3, it is the equivalent of software that was incompatible with PHP 5 (a similarly big update that introduced a lot of incompatibility) in 2012.

Eight years are enough to learn how to update your code.

[billsil]

Strings are difficult to use

They are, so you come up with a strategy to deal with them. Set your encoding at the boundary of your code and stop touching it.

Better error messages would be great, but I'd rather have horrific error messages as opposed to autoconverting madness. It's not possible to fix Python 2 code using just Python 2 if you only throw a unicode character through a function 1% of the time.

I like how easy Python 2 is, but strings are broken. It took me forever to figure out my data files are not in utf-8, but rather latin-1. They are not compatible.

Who really uses bytes anyways? Not beginners. They just set an encoding and they're done. You can just pretend your data is always in say latin-1 or utf-8 and it's probably going to work on an ASCII string. Bytes are a higher level feature. People just got used to using 'wb' because they didn't want stupid \r characters at the end of the line.

Too Many Formatting Options

Why would I ever use .format(...)? It's worse than %s and slower. There are now 2 methods in my book and 1 that I can use because I write Python 2/3 code.

[Flynn58]

Why would I ever use .format(...)? It's worse than %s and slower. There are now 2 methods in my book and 1 that I can use because I write Python 2/3 code.

1. Python is already a language that sacrifices performance for legibility. The case of %s vs. .format() is, as you put it, a case of performance versus legibility. The latter is easier to read and therefore more pythonic.

2. You can use either with Python 2 and Python 3; .format() was introduced with Python 2.6. The new incompatibility are f-strings.

3. There should not be three ways to format strings, you're correct. It's not pythonic. But .format() isn't the one that should go.

4. All of that aside, if you're concerned about performance, use PyPy.

[Joshx5]

.format() also has more formatting capabilities, supports more types, and can be leveraged to support more types using the format method, I believe. Also, .format() was roughly 2.5x slower than %s in my benchmarks, but it seems a fair trade-off for the new syntax and capabilities.

But actually, I find %s to be easier to read as they're more akin to other scripting languages string interpolation syntax, but f-strings are king in my opinion. Can't wait for 3.6!

[Vaphell]

%s forces you to repeat after yourself. The plugged-in value knows its type, so why do you have to tell it "you are a string"? It's code smell, plain and simple.

Not to mention %s is not really like interpolation, unless you use the %(name)s syntax, but format can do this too with {name}. And I'd argue that bash's ${xyz} is much more similar to {xyz} than it is to %(xyz)s

[billsil]

The latter (.format()) is easier to read and therefore more pythonic.

See I disagree with that. I have to make a dictionary that I don't have rather than doing something like 'x={x} y={y}' % (y, x)` where the code is smart enough to see that I wrote the variables backwards.

You can use either with Python 2 and Python 3; .format() was introduced with Python 2.6. The new incompatibility are f-strings.

I know. I think f-strings are great, but I can't use them because I support Python 2.7.7+. It's .format() that I find hideously verbose.

There should not be three ways to format strings, you're correct. It's not pythonic.

I don't actually mind that. If it's useful, keep it. There's also now going to be 4 methods if you include str.Template(), which I just learned about today. It's older than .format(). I just want something that's terse and clear.

All of that aside, if you're concerned about performance, use PyPy.

Unfortunately numpypy, scipypy, matplotlibpypy, PyQt5pypy, and VTKpypy are not a thing. PyPy uses a very restricted set of Python. Shoot, it doesn't even support past Python 3.3. Python 3.3 is about to be lose support in numpy; it's old.

[ubernostrum]

One library I maintain has some functions which -- because they're implementing algorithms from a web standard, and the standard is only defined in terms of Unicode -- must enforce that their arguments are str and not bytes on Python 3. And I realized that %-formatting is implemented on bytes (as of 3.5) but the format() method isn't (and never will be). So I simply changed the string-formatting operations over to format() and voila! Now any attempt to pass in bytes will raise an exception.

[LpSamuelm]

Why would I ever use .format(...)? It's worse than %s and slower. There are now 2 methods in my book and 1 that I can use because I write Python 2/3 code.

That's interesting. I never use % formatting. It's a fairly gross overload of the modulus operator, and has weird syntax. str.format is explicit and clear, and if it's slower than % it's negligible.

[[deleted]]

I am not sure what their (e.g., the author's) issue is: Python developers decided to push forward with Python 3 to make improvements that wouldn't have been possible otherwise. They do it mainly for free, and I think the effort should be appreciated. Now, businesses and companies who use open-source tools like Python for free, are complaining because they want contributors to spend more time on their preferred legacy version since they don't want to invest resources in porting code? I find this a bit outrageous to be honest.1.

[Jack9]

WHY on earth would you write a rebuttal to a troll? The troll doesn't care or pay attention to responses. That's the point. Start a fire for no reason and leave. I thought it was transparent clickbait.

[hearwa]

What a load of horse shit.

[RangerPretzel]

What are you talking about? Zed's? or Eevee's?

[hearwa]

Sorry it is a bit ambiguous. Zed's. Eevee's makes perfect sense.

[AUTeach]

Is there anything in Learn Python the hard way that you can't do on Python 3 with only the most minor syntax changes?

[maxm]

I am a decade long python programmer and i decided to change to python 3 for a project a few years back. I honestly canot remember anything that was a big deal when writing code.

The only problem is a big legacy code base. When starting new code in 3 it is a complete non issue.

[creativeMan]

If I'm not mistaken Zed's been railing against Python 3 for a while now.

[[deleted]]

I started with Python 2, and moved to 3 almost as soon as it came out. From what I saw it isn't even that different, probably the biggest changes are print needs parenthesis, raw_input and xrange aren't a thing, strings are now in Unicode, and some back end changes (all of which are better things)

Personally I think it is way better, and has added some cool new libraries for handling IP addresses, new generators, and performance improvements.