What are the drawbacks of Python?

http://programmers.stackexchange.com/questions/15468/what-are-the-drawbacks-of-python

by tchalla • 14 years ago

77 171 14 years ago

programmers.stackexchange.com

yen2233• 14 years ago

I never did understand why True and False are capitalized.

[EDIT: Turns out it's because all built-in constants are capitalized: http://stackoverflow.com/questions/521476/why-true-false-is-... . Learn something new every day. Still don't like it though.]

Also object-oriented programming in Python is very awkward. Then again, if I wanted OOP, I'd use C#.

Wickk• 14 years ago

How do you find OOP in python awkward? Out of curiosity.

yen2233• 14 years ago

All those self statements.

DeepDuh5• 14 years ago

Not the one you replied to, but one thing that hits me as awkward is the default static behavior of variables.

something like

  class Foo:
    bar = 1

means that bar is now a static class member (static in Java's sense). It needs to be assigned to "1" explicitly in __init__ as far as I understand. That's just unintuitive and leads to lots of boilerplate, just so that you don't need specifiers like 'static'. Sometimes the fear of verbosity gets in the way of intuitiveness.

rb2k_• 14 years ago

I always found it weird that they use len([1,2,3]) rather than [1,2,3].len

(no, I don't want to call [0,1,3].__len__() . Why would I want to add all of those underscores.)

nahname3• 14 years ago

Another response from a different source. Having to include self as a method argument means that those are not methods, but static functions. This really means there isn't precisely methods at all and the whole OOP part of python appears hacked together. That part seriously turned me off when I encountered it.

If there is a valid reason for this, it would go a long way in explaining away one of the major reasons I dislike python.

Edit: Appears to be a bug and I cannot respond to your post 'masklinn'. Can you rework the example to include the result as 42 being an instance variable instead? Thanks.

calvinlough• 14 years ago

The code to call super is awkward. Instead of saying super(MyClass, self).foo(), I would rather just say super.foo().

Having to specify self or cls as the first argument of an instance or class method. This one is weird when you are learning Python because you don't pass in the first variable but it gets magically inserted for you.

Creating a class method using a method decorator. Using a decorator to do something like this seems like a hack to me.

Not having a clean way to specify what all the instance variables are outside of the constructor. People with a java background are used to putting instance variable declarations as the first thing inside a class definition. In Python, these will be static variables. This seems weird and inconsistent with the how method declarations work (methods only become class methods when a decorator is used).

BTW, I like Python.

maglos• 14 years ago

I really like it's OO, it's regular and explicit. _ conventions are flexible for rapid development yet interfaces can still be hardened if required. You can do all sorts of stuff with decorators and Meta classes that you might do in macros in other languages but these are much more readable and predictable. The package system is simple and effective.

masklinn30• 14 years ago

> Then again, if I wanted OOP, I'd use C#.

Which is not just reductionist, but downright silly. C# is not a very good OO language, in the same way Java isn't.

When I want OOP, I play with Smalltalk. Or Self.

eropple2• 14 years ago

> When I want OOP, I play with Smalltalk. Or Self.

I'm reasonably sure there was an implicit "and be productive" in there. Smalltalk and Self are neat, but they don't do well on the get shit done test.

(Yes, I know it is possible to get shit done in those. Compare the difficulty of getting-shit-done in them to an environment like Java or C#, and an unbiased source is going to have to admit they fail pretty hard if only because of stuff like Maven or, to a lesser extent, NuGet.)

recursive3• 14 years ago

What's right with smalltalk and self that's wrong with c# and java? This is a serious question asked out of a desire to learn the answer.

hannibalhorn2• 14 years ago

Nobody has mentioned the inconsistent naming conventions in the standard library, which always drove me nuts.

ninetax• 14 years ago

Could you give some examples?

hannibalhorn2• 14 years ago

It's not a secret at all, PEP 8 even acknowledges it - see http://www.python.org/dev/peps/pep-0008/#naming-conventions - and of course attention to backwards compatibility is a good thing.

- usually constants are capitalized, but math.pi and math.e aren't

- the Decimal class has methods like is_nan(), and generally puts underscores in the method names, while the math package provides methods like isnan()

- even within the same package, you have cases like itertools.groupby() and itertools.combinations_with_replacement()

Not a deal breaker, it's just a drag when you only work in a language once every few months, and you constantly have to look at the docs to know whether something is alllowercase, ALLCAPS, camelCased, with_underscores, etc.

tocomment• 14 years ago

Did anyone mention the Gil? I'm hearing more and more complaints about that.

yen2233• 14 years ago

Having worked with multi-threaded applications in other languages, I'm starting to think that the GIL is more a good thing than a bad thing.

Seriously, threads are evil.

w0utert• 14 years ago

The GIL does not make threads less evil than you apparently already find them, it just makes them a lot less useful.

Threads in Python still have all the pitfalls and complications they have in other languages, it's just that they cannot use multiple cores or hardware threads. So you get all the evil bits (race conditions, deadlocks, having to protect access to shared state, etc), but you miss out on all the performance benefits threads can have on parallel hardware.

In Python, threads are only useful as an abstraction of things that have to run concurrently, even though they never do.

raverbashing2• 14 years ago

- Multithreaded development; multiprocess is being favored (as well as event-driven) and there are some helpful modules for it

- Unicode (at least for Python 2)

- Debugging is a little behind other languages (pdb works)

- removal of map/filter in place of list comprehensions (they are certainly better but not faster)

masklinn30• 14 years ago

> - Debugging is a little behind other languages (pdb works)

So do the numerous extensions/replacements for pdb, or the multiple graphical debuggers (e.g. PyCharm's, PyDev's, PuDB, WinPDB, Kodomo IDE's, Wing's, ...). Python doesn't have a time-traveling debugger à la OCaml, but that's about it as far as I can tell.

> removal of map/filter in place of list comprehensions (they are certainly better but not faster)

What are you talking about exactly? Because I find two possible interpretations of that phrase, and neither comes close to being correct.

raverbashing2• 14 years ago

Well, my mistake, map and filter are not faster than a list comprehension (at least not in 2.7)

My test case is: f = [x^2 for x in l if (x % 2) == 0] (and something similar with map and filter)

(where you read x^2 please consider x(double asterisk)2)

For 500k elements - xrange(500000) - this takes: 0.122527122498 (list comprehension) 0.145442008972 (map/filter)

denzil_correa• 14 years ago

An up vote just for Unicode in Python 2. It kills my life big time.

emidln3• 14 years ago

map and filter still exist. reduce was demoted into the stdlib instead of being builtin in 3.x.

list comprehensions generalize to other types (generator expressions (aka "lazy sequences"), set comprehensions, dict compresions)

Compare this syntax (using dict comprehensions in 2.7):

  {k:v for k, v in something.iteritems() if v == 3}

to this syntax using map/filter:

  dict(filter(None, 
           filter(lambda x: x if x[1] == 3 else None,
           something.iteritems()))

More frustrating to me is that there isn't an imap/ifilter builtin (I understand that it's in stdlib, I'm just lazy).

masklinn30• 14 years ago

> More frustrating to me is that there isn't an imap/ifilter builtin

FWIW, alongside the demotion of reduce to the stdlib Python 3 changed that, the builtin `map` and `filter` now return lazy "views" (as do e.g. `dict.items`, `dict.keys` and `dict.values`):

    # python 2
    >>> map(sys.stdout.write, ['foo', 'bar', 'baz'])
    foobarbaz[None, None, None]

    # python 3
    >>> map(sys.stdout.write, ['foo', 'bar', 'baz'])
    <map object at 0x10071cfd0>

emidln3• 14 years ago

I really wasn't awake when I wrote this, because that second example is awful. It should be:

  {k:v for k, v in something.iteritems() if v == 3}

  dict(filter(lambda x: x[1] == 3, something.iteritems()))

lazydon• 14 years ago

While we are on the subject, I find that this answer provides with much better arguments - http://stackoverflow.com/a/431341

It's an interesting read - he begins with "The problem is that it is not as good as it is made out to be, in other words it suffers from a degree of hype. I'll try to argue this point."

nahname3• 14 years ago

Mostly it is the age old complaint, can't build something big in a dynamic language. The evidence is that I don't know of anything big in a dynamic language. Not exactly great points against python when the argument boils down to, "all dynamic languages are bad."

d0m• 14 years ago

For what python has been created for, there are really few if any drawbacks. This is still my go to language.

Something I wish python had a better support would be truly anonymous function I.e. you can't do:

  lambda x: raise "foo"

It's also very hard to write nested callback (Some pythonists like to argue that is actually a good thing).

Lastly, I wish the functional paradigm part of python was more consistent.

But all in all, I love python and I find it very hard to switch to something new without missing it.

cageface2• 14 years ago

The scripting languages are all really more alike than different.

The main downside of Python compared to, Ruby, for example, is that Guido made some serious mistakes in the initial design and in the process of fixing them added a lot of extra complexity to the language. Python doesn't cleanly "fit in the head" the way Ruby or JavaScript do, at least for me.

But instead of wasting time micro-optimizing in such a narrow language space, pick Python or Ruby or whatever and spend your extra cycles on something different enough to be worthwhile like Go or Haskell.

cageface2• 14 years ago

I also think the python 3 transition came at a bad time. There are a lot more strong alternatives to python now than there were when the transition was planned so putting up with the hassles of migration is enough for some people to consider how green the grass might be in another field.

Guido always said he could only afford to break python once but it's not clear to me he'll even get away with once.

masklinn30• 14 years ago

> Python doesn't cleanly "fit in the head" the way Ruby or JavaScript do, at least for me.

I find the severe breakages and insanities of Javascript (such as tracking what `this` is) take much more brain-space than Python ever did, personally.

VeejayRampay2• 14 years ago

That "this" business is absolutely ridiculous. The fact that Javascript remains the SOLE language to script browsers in 2012 really really pisses me off. It is not a very good language in terms of design (even though it's been proved to be quite efficient and capable in the past few years).

lost-theory• 14 years ago

Did you learn python after you learned ruby or javascript? I have the exact same complaint about ruby not fitting in my head, and I think it's because I learned python first.

masklinn30• 14 years ago

I think part of the problem comes from them being so close syntactically and semantically, it puts the second one you learn in the uncanny valley, just close enough that your brain tries to reuse previous knowledge, just far enough that it can't and you get frustrated. I think that's especially the case if you don't have many languages under your belt.

When going from Python to Haskell, or Ruby to Erlang, you can't get confused between the two.

kamaal• 14 years ago

Python is easy.

Learning easy things and getting used to them makes learning difficult things tougher later.

dalke3• 14 years ago

"The scripting languages" is a very broad category. I think Python is rather different from Tcl, AppleScript, csh, JCL, MATLAB, and VBScript, to name but a few well-known scripting language. Ruby is definitely closer to Smalltalk (a non-scripting language) than it is to PHP (a server-side scripting language).

So I don't understand your comment about it being a narrow language space.

recursive3• 14 years ago

I learned python first, and I have the same complaint about ruby. When I was attempting to learn ruby, the subtle differences between blocks, procs, and proc.news, or whatever they are, seemed arbitrary and required too much thought to understand for my taste. In my brief exposure to ruby, that was symptomatic of a general trend in the language that there seemed to be many ways to accomplish a task, without a clear reason for the distinction. That's fine if you're writing code, but imo that's a feature that makes reading a language more difficult.

masklinn30• 14 years ago

> When I was attempting to learn ruby, the subtle differences between blocks, procs, and proc.news, or whatever they are, seemed arbitrary

As well as blocks not being first-class objects. Especially knowing a smattering of Smalltalk, that still feels weird.

VeejayRampay2• 14 years ago

You don't have to learn every single way to achieve a task though. Just sticking to simple blocks will solve 95% of the issues for you. If you want to get into more detail, Ruby will grow with you. I've sincerely yet to explicitly use lambdas or Procs and I've been coding Ruby through Rails for a few years now.

wonderzombie2• 14 years ago

I endorse Go as a substitute for Python. Seriously! It may read like a spiritual successor to C, but in practice, with type inference, GC, and struct/map/slice literals, it's very (as the golang people put it) light on the page.

tikhonj4• 14 years ago

I think "scripting language" is not the fairest identification. But not for the reasons most people don't like it: quite the opposite! For me, the issue is not that you can use Python or JavaScript for general-purpose development--although, of course, you can--but that you can actually use Haskell for scripting. And it's actually very good at it, too!

I've been replacing my shell scripts with Haskell scrips lately and the transition is going well. Soon the only two languages I will ever need are Haskell and elisp!

xyproto• 14 years ago

If only elisp was replaced with Haskell. One day, one day.

rbanffy• 14 years ago

> Python doesn't cleanly "fit in the head" the way Ruby or JavaScript do, at least for me.

I imagine the order on which you learn is important. I learned OOP with Smalltalk and C++ not only didn't fit in my head, it created an impressive allergic reaction. It took me 8 years to be able to get back to it and finally learn.

And it still feels a horrible kludge.

I learned Python before I had contact with Ruby and I find the irregular syntax hard to parse.

kanja• 14 years ago

That thread is depressing - most of the things people are complaining about are conscious design decisions made by the python team. EG Complaining about self - explicit is better than implicit is a core property of python. I feel like `import this` would answer a lot of these.

orangecat4• 14 years ago

Practicality beats purity. Python should support better function literals for the same reason that it supports the "implicit" [1,2,3] instead of making you explicitly create a list and call append. I'd say self falls into the same category, although I haven't found it as much an annoyance as some.

ErrantX• 14 years ago

Speed, definitely. Although in defence Ive always found python very easy to "hack".

Writing a C extension to do computationally intensive work is fairly simple.

With its versatility and extensability I once threw together a proof of concept password cracking cluster in a week. Redis for queues/data, MySQL for data, hashing code in a C extension, flask for the web interface. Cross platform and lovely :-)

Threading is the only real let down for me.

masklinn30• 14 years ago

> Writing a C extension to do computationally intensive work is fairly simple.

Even more so with Cython, which does most of the hard work for you.

Xixi• 14 years ago

Or the recent numba: https://github.com/numba/numba

njharman3• 14 years ago

There's so many solutions to the "speed" argument I don't even see it as an issue.

   - C-extentions (many std and 3rd party libs that need speed are written in C) 
   - numpy http://numpy.scipy.org/ 
   - numba https://github.com/numba/numba 
   - cython http://www.cython.org/ 
   - pyrex http://www.cosc.canterbury.ac.nz/greg.ewing/python/Pyrex/
   - http://psyco.sourceforge.net/ -> PyPy (some day...)

SoftwareMaven• 14 years ago

Where you were already using external queues, threads shouldn't have been an issue: just have multiple processes going (one for each core). Or use the processing package if you want more "threadlike" control.

It is unfortunate that you have to know that kind of thing a priori.

"Oh, look, a nice, built-in threading module."

Yes, BUT...

EDIT: I just re-read the way you wrote the "threading" comment and realized you probably weren't talking about it in the same context. Amazing what a word or two can do to understanding.

recoiledsnake• 14 years ago

Nice to see programmers.stackexchange.com being used for things like this. Hopefully it will put a rest to the same top comment on HN Stackoverflow stories complaining about how such questions are booted off Stackoverflow.com

njharman3• 14 years ago

If you learn to like Python, you will learn to hate other languages. :)

The stdlib. It has some great parts and overall is just good enough (and desire to not break everyone's code) to not cause revolt and wholesale replacement.

FTPlib is atrocious.

httplib/urlib mess -> requests

os os.path, shutil subprocess is a ridiculous mish-mash of legacy, obscurity and surprising behavior. One example. os.mkdir (but only the leaf, and exception if it exists), want mkdir -p behavior. Is that an option to os.mkdir, fuck no! We need a whole new function for such dramatically different feature. Must be called mkdirs, fuck no! That would be too easy to remember and no one every look at our beautiful docs. os.makedirs is the obvious choice.

masklinn30• 14 years ago

My biggest issue at this point is the implicit scoping. I've been using Python for 8 years (as well as a bunch of other languages, both for work and personally), and — while a lost cause, it won't be changed at this point — I've come to believe it was a Really Bad Idea[0].

Not only does it make bindings awkward (and sometimes broken, in different ways depending on the way "scope inference" is implemented) and tends to hide errors (e.g. typo) or generate them much later than possible (even though lexical checking is very cheap to perform at parse time, with explicit scopes), it has pretty much no actual benefit I can think of.

Especially in Python where assignment is a statement, not an expression, so it's not like explicit scoping would prevent putting assignments in place they're currently allowed.

[0] and it's one of the things I find utterly retarded in coffeescript.

emidln3• 14 years ago

assignment is a statement if you want it to be, but you can generally use setattr() as well. E.g. modifying global scope as an expression:

  import sys
  module = sys.modules[__name__]

  def foo(k,v):
      setattr(module, k, v)

  foo('spam','eggs')
  assert(spam == 'eggs')

dalke3• 14 years ago

I can't tell if the last bit is being sarcastic on bad naming, or it's an oversight: the function you want is called os.makedirs http://docs.python.org/library/os.html#os.makedirs and has been around since 1.5.2.

aptwebapps2• 14 years ago

It's sarcasm. njharman would have preferred mkdirs.

Alex39172• 14 years ago

"If you learn to like Python, you will learn to hate other languages."

I think it would be more accurate to say that if you learn other languages, you'll learn not to hate Python. Python is kind of mediocre in a lot of ways, but it's the only language without any deal breakers.

davidp• 14 years ago

> it's the only language without any deal breakers

Interesting thought. Can you elaborate?

pbiggar6• 14 years ago

Clojure also lacks deal breakers. Python was my least hated language until Clojure.

whalesalad2• 14 years ago

I'd like to think/hope that no one would ever judge a language on it's FTP library =)

rjh29• 14 years ago

My favourite critique of Python: http://www.quora.com/What-are-the-main-weaknesses-of-Python-...

lectrick• 14 years ago

self __init__ self.__init__ self self __init__ self

lani• 14 years ago

it doesn't wear a suit

topherjaynes• 14 years ago

Is this a quote from somewhere? I laughed, and now want to make a opensource project suitupy

calpaterson2• 14 years ago

This thread mostly contains superficial complaints (whitespace, self, the GIL) that are either explicit design decisions or not important for the kind of programming Python wants to address. Some more important problems that materially affect normal and sane use of Python:

- Broken scoping by default (the thread does raise this)

- Unicode is very painful in python2 (addressed very well by python3)

- Duck typing sometimes prevents early detection of genuine programming mistakes because of overuse: False + 1 == True

- No good isolation tools (virtualenv, the most common tool, silently fails to isolate dependencies when moved, which is obviously makes it tough to deploy using it)

- Poor packaging tools (only a few tools than they all have serious limitations such as not being able to package c-extensions).

- Some of the standard library is downright terrible. csv and robotsparser are good examples. This has the pernicious effect of widely-distributing libraries that have subtle but serious drawbacks.

tarekziade2• 14 years ago

> Poor packaging tools (only a few tools than they all have serious limitations such as not being able to package c-extensions).

Python stdlib will let you package a C extension. I am not sure why you think the opposite. http://docs.python.org/extending/index.html

> No good isolation tools (virtualenv, the most common tool, silently fails to isolate dependencies when moved)

If you mean it's not relocatable, there's a new option for this http://www.virtualenv.org/en/latest/index.html#making-enviro...

But being not relocatable is not really an issue, as you can simply re-run virtualenv in the new place. All libs you previously installed will work without having to install them again

> Some of the standard library is downright terrible. csv and robotsparser are good examples. This has the side effect of widely-distributing libraries that have subtle but serious drawbacks.

Some stuff in the stdlib are not good that's true, but we have a gigantic library ecosystem at pypi.python.org will very well written piece of libs. Using Python seriously, I have never ever felt the serious drawbacks you are talking about except with tarlib in python 2.4 which was seriously broken.

calpaterson2• 14 years ago

> Python stdlib will let you package a C extension. I am not sure why you think the opposite. http://docs.python.org/extending/index.html

But c-extensions aren't put into the same package so you still have to include the shared object files yourself so it's not really a package. One of the best things about the JVM's jar is that you can pack all your other jars into one jar for deployment.

> If you mean it's not relocatable, there's a new option for this: (--relocatable)

"In theory virtualenvs have a --relocatable flag but that one is heavily broken and conceptionally can't work properly because it uses the system Python interpreter to switch to the intended environment."

http://lucumr.pocoo.org/2012/6/22/hate-hate-hate-everywhere/

> pypi.python.org

Yes, it's great, but I'm talking about the standard library. I really wish some of the worse parts of it would be improved or removed.

cdavid2• 14 years ago

Quite a few poor and superficial answers in that link. The usual argument that dynamic typing does not scale for large projects is largely unfounded. There are large projects in Lisp, I don't get why people don't use the dynamic card as often there. What I have seen happened on badly engineered large projects is people blaming it on dynamic typing because there is no documentation and no structural integrity in the project. But the people behind those projects would not be able to do much in any language IMO. In a sense, it allows for poor programmers to do more.

The speed issue is a significant one, but not usually for the reasons given. The big drawback of being slow means a lots of its implementation is not written in python.

IDE/debugger is another issue, although some of it is a matter of people not knowing the tool. Especially on bad codebases, even something as simple as pyflakes running in the background is invaluable, and many people don't use this.

theorique• 14 years ago

In a sense, it allows for poor programmers to do more.

Exactly. Dynamic typing can provide a temporary fig leaf for bad design in ways where static type checking would be less forgiving. Doesn't make dynamic typing wrong, it just means that bad programmers can get in over their heads more completely and more quickly.

dkarl2• 14 years ago

What I have seen happened on badly engineered large projects is people blaming it on dynamic typing because there is no documentation and no structural integrity in the project.

This can be a problem in static languages with good type inference, too. When reading code in older static languages like C++, you'll find a bunch of variables and types declared, but powerful and concise languages such as Scala have much less use for intermediate variables, and type inference means that intermediate variables are almost never declared with a type. Field types and method return types often aren't declared either. I don't know if this is a good thing because it forces you to read a lot of code, or if it's a bad thing because it forces you to read many unrelated bits of code when you're trying to get something simple done.

eru3• 14 years ago

In theory, your IDE/editor should cooperate with the compiler and display the inferred types for you, if you choose so.

spitfire• 14 years ago

That's because C and C++ are not static languages. Only people who leaned C and C++ first think they are.

wonderzombie2• 14 years ago

I've been digging into Clojure and reading Paul Graham's On Lisp. So I've been wondering about Python vs. Lisp lately, esp. on the topic of dynamism. I wish I knew more about Lisp to delve into this further, but your first para caught my eye.

Is it not the case that in Lisp people tend to use values — lists of (probably immutable) data — rather than objects? Objects are in and of themselves their own flavor of custom, specialized language for interacting with a data structure. In Lisp, the language for interacting with lists of lists or what have you is, well, Lisp.

IME duck typing is not a real answer in this situation; that helps when you are programming to an interface in the standard library, or in an API you are using. Otherwise I end up hunting down information about a data type through N layers of method and function calls. Not a good time. :( This actually drove me towards Go as a language with comparable productivity but with a type checker, et al.

I'm not sure where Lisp macros fit into this, if they do. I expect they have a tendency to boil down frequently repeated patterns into something very compact and less error-prone.

As for IDE support, Rob Pike suggested (not in so many words) that if you need an IDE for your programming language, it suggests that something's probably wrong with that language. He's not disputing that people genuinely need them, because yes, jesus h, I really do need Eclipse when you're programming against a reasonably large API. I think I find this line of reasoning more convincing than I would have, say, a year or two ago.

Anyway, for my part, ST2 was enough of a Python IDE for me. And thanks for the tip about Pyflakes, by the way. There's guard[1], which I figured you could rig up with python -c or whatever the flag is to compile. Pyflakes looks easier.

[1] https://github.com/guard/guard

masklinn30• 14 years ago

> Pyflakes looks easier.

Look up flake8, it runs both pyflakes and pep8, and can optionally warn about cyclomatic complexity as well.

cdavid2• 14 years ago

I would say that idiomatic python code often does not overuse objects. Lack of immutable data is indeed something I miss (especially COW dict/list/set).

One thing that is clearly overused in python code is dictionaries to pass data where the set of keys is fixed and known, or worse passing dict with different set of keys instead of proper 'modelling'. Things like traits (http://code.enthought.com/projects/traits - disclaimer, I work for Enthought ), or even simple libraries like remoteobjects (https://github.com/saymedia/remoteobjects) can be helpful in those cases.

I myself don't use IDE much: I am too entrenched with vim to gain enough from an IDE, although pycharm is quite nice. I would much rather see libraries around things IDE do ('live' 'AST' of a whole project, good refactoring, debugging) so that one can integrate them in whatever environment people use. I think we are going there (https://groups.google.com/forum/?fromgroups#!forum/python-st...).

Go does look nice, but it misses two killer features for me: NumPy and the whole scipy ecosystem, and C integration (in both directions). I think the python community itself does not realize how big and significant the scipy ecosystem is (nothing comes anywhere near in any common language AFAIK).

LBarret• 14 years ago

I have built an app of over 500k sloc in Python.

In retrospective, I feel the python as a language was a good choice, it helped us move very fast and do a lot of things :

- One good pythonner is very productive

- It was easier to get someone aboard, it is easy to get python and to reasonnably efficient with it.

- there are libraries for everything.

- going to cython or c++ was always an easy alternative for those crtical part of the code.

The only cases where python can be problematic are :

- high reliability code like trains or planes software, because python code is not provable.

- very high performance, where the slowness of python in the not critical part of code can be a problem.

Besides, It doesn't protect you against the classic problems of a big codebase built by a different of people over a period of time. Tools like pynocle or pylint were good for this.

So, in the end, python has obvious weakness. Most of the time It seems like a solid choice (among others). Right tools for the job, etc.

orangecat4• 14 years ago

Python has been my favorite language for many years, while the last few months at work I've been writing a lot of JavaScript. I've found that JS has exactly one advantage over Python, which is usable function literals. And that turns out to have a surprisingly large impact. It's convenient and natural to create "anonymous classes" that use closures to store their state, while in Python you'd have to manually create classes and manually copy the variables in __init__. I really wish Python could gain something like that while retaining its many advantages.

whalesalad2• 14 years ago

I've been heavily involved with python and javascript for most of my programming life and find them to be very similar. It's a joy to write in either language.

tikhonj4• 14 years ago

JavaScript also has much better scoping--Python's using = for both defining and setting variables makes life much more difficult.

masklinn30• 14 years ago

> JavaScript also has much better scoping

Though I generally agree, that's as long as you mandate linting. JS's implicit globals are even worse than Python's implicit scoping.

hiddenbayes• 14 years ago

Adding a "var" keyword, similar to that of Javascript, was discussed on the Python mailing list a while ago. See here:

http://mail.python.org/pipermail/python-3000/2006-October/00...

btilly2• 14 years ago

What do you mean by "usable function literals"? Because Python has them, even if you have to do a bit of work to get them.

    def demo (n):
        def multiplier (m):
            return n * m
        return multiplier

    x5 = demo(5);
    print x5(4)

You can do anything in the inner closure that you might want. The only surprise is scoping - if you want to modify state you need to use a mutable data type because otherwise you'll be instantiating a private variable. But that hoop is easy to handle.

    def demo ():
        counter = [0]
        def increment ():
            counter[0] += 1
        def peek ():
            return counter[0]
        return (increment, peek)

    (increment1, peek1) = demo()
    (increment2, peek2) = demo()
    increment1()
    increment1()
    increment2()
    print peek1()
    print peek2()

So there. Function literals. They work.

But, you say, you really want anonymous classes? Well look up metaprogramming then. Python really has quite good support for it. There is no trouble creating anonymous classes on the fly with their own attributes, functions, and so on. They can even inherit from each other. http://www.voidspace.org.uk/python/articles/metaclasses.shtm... might be a good starting place on this for you.

(Note, I do not recommend metaprogramming unless the solution you make will be reused a lot.)

orangecat4• 14 years ago

What do you mean by "usable function literals"?

lambdas. Your example isn't a literal, it's just a declared function named "multiplier". Sure, it has equivalent functionality, in the same sense that Python could remove collection literals like [1,2,3] and you could still create lists and maps by hand. But that would be silly.

even if you have to do a bit of work to get them

And that work means that useful techniques become too unwieldy to use in practice.

sitkack• 14 years ago

My similar solution is here https://gist.github.com/3678958 it has the added bonus of using an object with the methods attached, but the outcome is the same.

pbiggar6• 14 years ago

My least favourite part of python (I'm overwhelmingly a fan, and it's probably my favourite language after Clojure) is the deliberately limited functional parts. Take list comprehensions, they work for simple things, but when you want to make it more complex, it wont let you break it over multiple lines, so you have to rewrite it into a for loop. Makes debugging awkward.

masklinn30• 14 years ago

> it wont let you break it over multiple lines

    result = [
        (value, process(value), process(key, value))
        for key in generator
        for value in generate(key)
        if some_condition(key)
        if other_condition(value)
    ]

or did you mean something completely different? Maybe the problem of not being able to use statements in comprehensions (or lambdas)?

pbiggar6• 14 years ago

Right, I meant using statements, sorry. It's been quite a few months since I wrote python, so I think I've forgotten most of the details.

Daniel_Newby• 14 years ago

Just define a nested function above and call it in the list comprehension.

pbiggar6• 14 years ago

Same problem - I have to rewrite my lovely list comprehension instead of just adding a statement to the body.

tptacek3• 14 years ago

"It's far from the metal"? No it isn't. It has ctypes, which is one of the best FFIs I've worked with. I wrote a trampoline-injecting kernel debugger in it. I don't love Python, but that answer disqualifies itself.

_dps• 14 years ago

You're probably aware of LuaJIT (http://http://luajit.org/) already but I'll toss it in for other readers: as a former heavy user of ctypes, after discovering LuaJIT and its FFI I haven't touched ctypes again. For people who need to do this kind of work, it's worth looking into (enough so that one of the core PyPy developers is emulating LuaJIT's FFI design in the project Python CFFI http://cffi.readthedocs.org/en/latest/index.html).

Sukotto2• 14 years ago

I don't know what trampoline-injecting means and my googlefu has failed me. Would you briefly explain what you mean?

tptacek3• 14 years ago

Instead of implementing breakpoints with INT 3, which relies on the OS's debug event support, our debugger injected new basic blocks into the program to pause the target, perform I/O with it, and redirect it to other code paths.

You should have no trouble looking up what a "trampoline" is, but I'm abusing the term a bit.

tikhonj4• 14 years ago

My biggest problem with Python is not that it's a bad language but that it isn't a great language. Why is this an issue? Simple: it's one of the most highly rated--and, frankly, overrated languages today. And, try as I may, I can never seem to get away from it: at least in my circles, it's even more endemic than Java!

I really wish people liked OCaml or Haskell that much instead.

snogglethorpe• 14 years ago

Yeah. Python has an awful lot of warts, considering the way so many people fawn over it.

Really the main strength of Python is not the language at all, but the huge number of libraries written for it, and the wealth of tools and "community." Fair enough, it was in the right place, at the right time, but if history is going to throw its weight behind something, it is a little annoying when that thing is rather mediocre...

pnathan• 14 years ago

I've written about this before here: http://news.ycombinator.com/item?id=3580590

Fundamentally, I believe Python's drawback is that it appears to draw heavily from the ABC history it has, and wasn't designed for power and flexibility.

I'd rather use Perl, Ruby or Lisp.

monochromatic• 14 years ago

Mutable default arguments. 'nuff said.

gizmo6864• 14 years ago

Ironically, the one time where I noticed this bug was while testing a component, whose only use involved me emulating the behavior of mutable default arguments on a higher level. I still think it is a horrible system. My strong opinion on it might be because I spent hours looking at our c-extensions for the source, because the previous two 'language bugs' I ran into were both in our c-extensions, where we had a type that could not cast to it self, and someone thought it was a good idea to make ~x mean x-1.

anuraj• 14 years ago

Performance and type safety which is true for any scripting language

16s• 14 years ago

I would say that Python has a feeling of inconsistency at times compared to other scripting languages. I don't mean this as a criticism. I like and use Python a lot for work and personal projects. Here's an example of what I mean by inconsistent:

len(a_string)

a_string.lower()

a_string.upper()

So here, there's a global, generic function len() that returns the length of the string while in the other examples, the string has methods such as .lower() .upper() etc. Why not have a_string.length()? I understand that generic functions are more efficient and even proper in OO. It just causes the feeling of inconsistency when you use the language a lot or when you are teaching a child how to program and have to explain the difference and why some things are methods while others are not.

Also, some python idioms (such as slicing) are not intuitive for many use cases. Here's an example of the traditional way in which to reverse a string in Python by slicing:

a_string[::-1]

In Ruby, you type a_string.reverse() and that is much more intuitive to a child when compared to the slicing in Python.

Having said all of that, I love Python and use it daily and encourage others to do so as well. I

silverlake• 14 years ago

I was a Lisp/Scheme programmer. I use Python only because Norvig wrote that it isn't so bad. But I curse out loud every time I type in 'self'. I hate the lambda limitation (only expr). The scoping rules continue to confuse me. It's a good language if you're coming from C/Java. But it's a poor language if you're coming from Lisp/Smalltalk/ML.

DonnyV• 14 years ago

To this day I still hate the fact that wrong spacing causes a compiling error.

What are the drawbacks of Python?

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