[Python-Dev] Python 2.x and 3.x use survey, 2014 edition

[Antoine Pitrou]

On Mon, 15 Dec 2014 19:08:17 -0800
Mark Roberts <wizzat at gmail.com> wrote:
> 
> So, I'm the guy that used the "hate" word in relation to writing 2/3
> compliant code. And really, as a library maintainer/writer I do hate
> writing 2/3 compatible code. Having 4 future imports in every file and
> being forced to use a compatibility shim to do something as simple as
> iterating across a dictionary is somewhere between sad and infuriating -
> and that's just the beginning of the madness.

Iterating accross a dictionary doesn't need compatibility shims. It's
dead simple in all Python versions:

$ python2
Python 2.7.8 (default, Oct 20 2014, 15:05:19) 
[GCC 4.9.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> d = {'a': 1}
>>> for k in d: print(k)
... 
a

$ python3
Python 3.4.2 (default, Oct  8 2014, 13:08:17) 
[GCC 4.9.1] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> d = {'a': 1}
>>> for k in d: print(k)
... 
a

Besides, using iteritems() and friends is generally a premature
optimization, unless you know you'll have very large containers.
Creating a list is cheap.

> From there we get into
> identifier related problems with their own compatibility shims - like
> str(), unicode(), bytes(), int(), and long(). Writing 2/3 compatible Python
> feels more like torture than fun.

It depends what kind of purpose your code is written for, or how you
write it. Unless you have a lot of network-facing code, writing 2/3
compatible code should actually be quite pedestrian.

Regards

Antoine.