Create a virtual environment for the Python version you want to use, and install the package with pip (pip will install all the dependencies in your project's local environment)...
$ mkdir myproj
$ cd myproj
$ virtualenv --python=python2.7 env
$ source env/bin/activate
(env)$ pip install somepackage $ mkvirtualenv env1
(env1)$ pip install somepackage
Like I say, I've probably just been unlucky. But at this point it's given me a pretty serious aversion to Python. Will probably have to get over that someday, I suppose.
Virtualenv and PIP go a long way towards fixing these problems in Python, similar to how PEAR and CPAN work with PHP and Perl.
I'm completely lost as to why you think this is a problem with Python or its standard library. (Except that this seems like an opportune venue to bash a perceived competitor to your favorites)
It was years before I even saw any need to use virtualenv, (and that was because of misbehaving packages from Google and a desire never to modify PYTHONPATH again).
About documentation, again I feel strongly that you must have used some specifically bad package and again I can't say how I see that to be an inherent flaw with Python or its standard library.
"Pure" is one of the last things I'd call Python. For example, imperative constructs are jumbled with OO constructs and functional constructs.
I've found I can mitigate most of this by using perlbrew/cpanminus, pythonbrew/pip and rvm/gem.
This adds complications when it comes to deployment - you've added additional maintenance dependencies to your servers if you don't stick with what the package manager provides... Nothing insurmountable, but keeping an eye on updates (would usually use email to notify on dated versions) and maybe having your CI system always use the latest versions of everything are possible methods. I'd like to hear better ideas, to be honest.
My background is both sysadmin and development, I think there should be no reason we can't make this all simpler for everyone.
At least in Python, the problem occurs because distros make several mistakes which build on each other. (A) insist on generating their own packages for modules (and typically, taking forever to update them). (B) not providing any kind of isolation. (C) building on top of these non-isolated modules.
What I do these days is leave the system Python 100% for the use of the distro (at most, dependencies for minor command line scripts which don't have import relationships with code I'm working on). Development occurs inside virtualenvs, production apps run inside virtualenvs. I use pip to install, remove, pin versions.
Dependency versions are really part of the app; the right versions should be pip installable inside a virtualenv, and this is just something which should be done automatically on a deploy. I don't mean you need to include the whole code for your dependencies in your project, but pinning versions is important to not having to put out fires.
You really don't want any versions to advance automatically until you have had a chance at least to run unit tests - if things are working then pin the new version. Of course, if you are using a library which never suffers regressions or API changes then you don't need to do this.
In short, the dependency list and versions should be included with the project and managed by the developers so that deploys are really a matter of creating a virtualenv (with --no-site-packages) and running pip -r requirements.txt to install the right stuff.
I've had the same experience before, but chiefly with Ruby.
Interestingly, my problems with this in both Python and Ruby have evaporated once I got in the habit of using virtualenv/rb-env/rvm for my development environment.
Python is about the cleanest/nicest experience I have in any language, for the record. Only language that comes close is Clojure.
Leiningen is...legendary.
Suppose you want to do a very common task like parse some XML. In Clojure, the workflow is:
1. Go to Github or Clojars, find the latest version number of clojure.data.xml
2. Add this version number to your project.clj
3. Lein deps and restart the repl
4. Re-acquire whatever REPL data you had
1. import xml.{sax,dom,etree}
_domains_text = requests.get(API_URL + "/domainlist.xml").content
_domains_db = pyquery.PyQuery(_domains_text)
DOMAINS = [d.values()[0] for d in _domains_db('domain')] jQuery = pyquery.PyQuery(someHTMLDocumentString)
links = jQuery('a')
Tell me about it: http://lee-phillips.org/badruby/
That in itself would not be reasonable. But it seems as if Ruby's own libraries broke going from 1.8.1. -> 1.8.7. Regardless of the number of years involved, that's kind of unexpected. But I'm not familiar with the Ruby world, and maybe that change in version number is considered major.
The whole experience left me with reduced confidence in Ruby stuff and I still avoid it and programs that use it. The comments below by people who know more about the Ruby ecosystem than I do don't give me any reason to change.
The problem is that the various packaged versions of Ruby are a shambles. RVM has a number of significant problems and difficulties (rbenv is both better and worse).
Right now getting a good, modern Ruby version on a standard modern computer is a big pain in the ass.
As long as that stays true, we will be dinged for not supporting old (but common) versions.
Years from now, when everybody has good 1.9 compatibility, things may be better. At least, if 2.0 doesn't have the same problems...
So many of the language features have changed in ruby programmer will have to edit every file in her project, and upgrade every single dependency, just to get her application running on a new ruby interpreter. Add that to the culture of "let's use as much 3rd party code as possible!" and the library writers emulating the core developers and changing their APIs all the time ... the process of upgrading an interpreter converges on "rewrite the entire application"
Which is what we do. And some percentage of those rewrites are in languages that don't have this problem.
That said: Leiningen & npm _are_ really nice solutions for me.
I don't have this problem on either Ruby or Java.
As much as people love to bash PHP -- and I agree that it's pretty awful as a language -- its standard library is so comprehensive, backwards-compatible, and superbly-documented that I have never had a comparably aggravating experience with it. The same is true of Javascript: a language with warts, but whenever I try something, it Just Works.
Like I say, perhaps I've just been unlucky, but my distinct impression of Python has been that it's a beautiful language surrounded by a particularly problematic ecosystem of incompatible libraries and sparse documentation. I suspect that the Python community would benefit from paying less attention to the purity of the language, and a lot more attention to the quality of everything surrounding it.