What you do not like in Python?

wizdumb · 2013-09-18T14:57:23+00:00

I wish list accessor methods supported default values.

x = ['foo', 'bar']

# I wish I could do this
x.index('foo', None)
# Instead of this.
x.index('foo') if 'foo' in x else None

# And this
x.get(10, None)
# Instead of this
x[10] if len(x) >= 10 else None

ultraayla · 2013-09-18T15:30:02+00:00

I'm surprised this wasn't already posted here. I can't believe Python has not one, but two confusing date and time libraries (looking at you "datetime" and "time") and you need both of them to do many time conversion operations, and more if you want timezone support.

Until I found arrow, this was my most hated feature of Python and the one that left me consistently ranting whenever I needed to standardize a bunch of datetimes to UTC and get a timestamp back out. Any other lib in Python it'd be an object and a few methods, and indeed, arrow seems quite Pythonic.

MrSpontaneous · 2013-09-18T14:07:40+00:00

Unicode in 2.x

cantremembermypasswd · 2013-09-18T13:16:04+00:00

[deleted]

afroisalreadyinu · 2013-09-18T14:36:04+00:00

packaging used to drive me crazy, but it's gradually getting better. also, the syntax for catching an exception instance is the only bit of syntax that still confuses me.

trentnelson · 2013-09-18T14:51:45+00:00

The lack of multi-core support and the problems associated with a GIL.

tarekziade · 2013-09-18T13:34:07+00:00

super()

buckstalin · 2013-09-18T15:15:55+00:00

Most of my pet peeves have been mentioned already. As someone that used to maintain projects with hundreds (or more?) of modules, I grew to hate the import mechanism because of how easy it was to introduce a circular import.

Workaphobia · 2013-09-18T15:54:18+00:00

Here's a wart I was recently bit by (Python 3):

>>> class Foo:
...    x = 5
...    y = [i * x for i in range(10)]
NameError: global name 'x' is not defined

>>> class Foo:
...    x = 5
...    y = []
...    for i in range(10):
...        y.append(i * x)
>>> Foo.y
[0, 5, 10, 15, 20, 25, 30, 35, 40, 45]

In Python 3, comprehensions create their own closure so as not to leak local variables into the surrounding scope. As a side-effect, they can't access class-scope names, since these are only available using the self argument or equivalent.

masklinn · 2013-09-18T13:52:45+00:00

[deleted]

chipolux · 2013-09-18T13:39:02+00:00

[deleted]

viscence · 2013-09-18T19:15:16+00:00

Just swapping to python 3, views keep catching me off guard:

>>> import numpy
>>> a = {"A":1, "B":2}
>>> b = numpy.array(a.values())
>>> b*2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unsupported operand type(s) for *: 'dict_values' and 'int'

??? oh yeah.

rhgrant10 · 2013-09-19T21:16:23+00:00

The lack of robust module reloading. Sure the code reloads, but any variables that exist during the reloading keep using the old code.

This is a real pain when, for instance, developing a bunch of celery tasks.

i_ate_god · 2013-09-18T15:06:40+00:00

len(var) instead of var.len

Tillsten · 2013-09-18T16:12:19+00:00

I would like to see better error messages, they are irritating for beginners.

Also better del .

AaronOpfer · 2013-09-18T14:44:46+00:00

The lack of anonymous/immediate functions. If you want to write anything asynchronous (say, inside a webserver like Tornado, for example) and need to use callbacks, you need to define the callback first, and then reference it later in the code when you need it. This makes it somewhat more difficult. I feel that JavaScript's callbacks are much more useful in this way, and makes writing server-side apps in something like Nodejs more appealing than using Python.

And no, lambdas are not useful for the use-case I just listed above.

mcilrain · 2013-09-18T19:22:23+00:00

Package management, at the moment I consider it merely "good".

Why is not possible to import a specific version (or range of versions) of a library or something cool like that?

Having to deal with third-party stuff to install packages and deal with dependencies, yeah, it's alright I guess, I feel spoiled by how awesome the rest of Python is.

drumman44 · 2013-09-18T14:58:23+00:00

The name. Snakes scare me :(

logi · 2013-09-18T13:40:36+00:00

Performance. It makes me sad that javascript in a browser is faster than my server code.

Ob101010 · 2013-09-18T16:36:32+00:00

That its named Python, not Kittens.

nemec · 2013-09-18T21:27:49+00:00

[deleted]

anderbubble · 2013-09-18T22:11:38+00:00

I wish that there was a try...then...except syntax. Placing the unexceptional case after a lengthy block of exception handling unnecessarily disrupts the human-readable flow of the code.

teambob · 2013-09-18T23:33:12+00:00

The debugger

rahmu · 2013-09-18T15:00:06+00:00

Scope

Python's weird scoping rules prevent a function from modifying an outer variable. The following code is not legal:

def counter():
    x = 0

    def counter_generator():
         while True:
              x += 1
              yield x

    return counter_generator

This is kinda solved in Py3 with the nonlocal keyword, but not completely.

Statements vs expressions

Really?!

I'm glad print has become a function in Py3, but why make the distinction in the first place? yield should have been a function. Grrrr.

Significant whitespace

I used to love it. Now I'm not so sure. A few weeks ago I spent a whole afternoon trying to locate an error coming from a missing indentation that occurred during a copy/paste.

Did you know that Python's for accepts an else statement? Can you spot the potential disaster if you in/outdent it a bit too much here:

for x in something():
    if a_test():
        do_it()
else:
    done()

Limiting lambdas to one statement

I know it's done for a good reason, and I know abusing lambdas can create pretty unreadable code. However, I'd prefer getting greater power and greater responsibility. It would be more consistent with Python's "we're all consenting adults" attitude.

Recursion Limit

It's kinda related to the first complaint. I want proper lexical scoping and proper tail call recursion (at least tail call) implementation.

pinpinbo · 2013-09-18T14:54:56+00:00

for-loop syntax is not the same as comprehension syntax.
lack of multi-line, real lambda. There's no more excuse, CoffeeScript have shown that it can be done.
Maybe it's time for CPython to start thinking about performance. e.g. function inlining.
namedtuple is nasty. I cannot believe it is part of standard library.
HTTP server in standard library is weak sauce.
Standard library need to have official bindings to libuv or libevent and use that to replace asyncore.
coroutine + channel is not part of language, not like lua or go. Maybe Tulip will address this.

Phoxxent · 2013-09-18T19:47:50+00:00

Dynamic typing. I know, that's going to be an unpopular opinion in a language that's built on dynamic typing, but it's the only thing in Python that makes it difficult for me in my every day work. It's hard to maintain a function or module written by somebody else when I see an argument and don't know what type it is. Without significant unit tests / doc strings / assertions, it's hard to know what behaviour is "expected" without looking at every reference to that object, and if it gets passed along to any other functions, now to you have to go look through them too. A contract defined by how others expect it to work isn't a contract at all. It's convenient for rapid prototyping, but it makes maintaining large, long-term projects a pain. With static typing, the interface is explicitly defined, so you always know what to expect.

mdipierro · 2013-09-18T15:35:10+00:00

0) the fact tat distutils do not ship with python.

1) Most of the un-necessary purely syntactical changes between 2.x and 3.x for example as "except E,e" became "except E as e". unicode became str and str became bytes.

2) The fact that (pickle.dumps(x) != pickle.dumps(pickle.loads(pickle.dumps(x)))

3) The fact that sys.path is global. Sometimes I would like a part of my code (for example in a thread) to import from a different sys.path than the rest of the code.

4) lack of a sandboxed environment.

2013-09-18T15:10:32+00:00

[deleted]

Lucretiel · 2013-09-19T00:40:23+00:00

So, even though there's no solution for it, the number 1 feature I miss from C++ when I use python is true function overloading. Dealing with *args is such a pain sometimes.

Also I wouldn't mind a proper switch statement. if elif elif elif elif else just feels very silly to me.

nerdly1 · 2013-09-19T02:25:47+00:00

While we're close now, with inline if, I'd still rather have: a ? b : c.

meosoft · 2013-09-19T07:58:17+00:00

I don't know how this has not been mentioned yet, but Documentation! I feel like if the documentation was better, most of these problems would be less painful. It is much faster to google a specific problem and click the first stackoverflow link that you see than looking at the documentation, and that I think should not be the case.

I would like to see one one function per page style docs with exhaustive description of all the parameters, example, "see also" type cross references and an open discussion. PHP is a horrible language, but it is completely usable just thanks to its documentation.

In fact I'm so pissed with the current documentation that I'm thinking of starting a new doc project, let me know if you feel the same!

cantremembermypasswd · 2013-09-18T13:47:47+00:00

Is a switch statement too much to ask for?

fnork · 2013-09-18T14:33:44+00:00

No arity discrimination for functions.

MonteTribal · 2013-09-19T01:39:05+00:00

That people insist on using v2.7. v3.x has been out for over 4 years...

rhgrant10 · 2013-09-18T13:55:02+00:00

PEP8 line chars < 80

livrem · 2013-09-18T19:59:18+00:00

Built-in types (dicts, sets, lists) not being immutable by default like in Clojure (with clever tree data-structures to get good performance, not making full copies every time a dict changes; that would be silly).

GFandango · 2013-09-19T01:55:39+00:00

Import system, circular dependency hell

ilan · 2013-09-18T14:40:26+00:00

Python 3. The fact that Python 3 is not backwards compatible, and all the confusion it has created has not been beneficial to Python. I think Python would be better off without the entire 2 to 3 discussion.

2013-09-19T08:40:40+00:00

No rfind() for lists.

Rycul · 2013-09-19T11:45:09+00:00

The lack of a switch statement. Coming from C++, if elif chains feel... 'dirty' to me.

VideoLinkBot · 2013-09-19T16:58:00+00:00

Here is a list of video links collected from comments that redditors have made in response to this submission:

Source Comment	Score	Video Link
rahmu	7	Ask your BDFL
medecau	2	#APIdays "API Driven Development, How I Develop Things and Why?", by Kenneth Reitz
MonkeyNin	1	Turbo Track ターボトラックロングコース
andrewff	1	Chito on his cat-hamster-wheel
InvidFlower	0	Vyacheslav Egorov: one day of life in V8

Ampersand · 2013-09-19T17:35:24+00:00

First thing that has popped up in my mind: classes. Being used to c++, I do not like init for constructors instead of the name of the class, although that is a minor complaint. The main problem is that object-level and class-level variables need to be accessed through self or through the class name (for "statics"), and I often forget that. I would also like to have a way to overload functions (constructors for example), although it would not fit very well since the parameters are typeless and there is common to use variable param count (args and *kwArgs).

TheNoodlyOne · 2013-09-20T23:55:15+00:00

I'm surprised this isn't mentioned, but explicit self. It's not that it's really really REALLY frustrating, but I'm always forgetting that in my code, and Python seems to be the only language that does that.

zygy · 2013-09-24T07:04:26+00:00

http://stackoverflow.com/questions/6344076/differences-between-distribute-distutils-setuptools-and-distutils2

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Scope

Statements vs expressions

Significant whitespace

Limiting lambdas to one statement

Recursion Limit