如果从python2.6导入要与python2.7一起使用的站点包，可能会发生问题？

Question

I finally managed to install numpy, but it seems to only work in python2.6 . I don't know how to install it in the 2.7 folder (been trying for hours, but I'm just a beginner developer in my first months). Anyway, if I use Python 2.7 and append the absolute path to sys.path, could there be problems?

Any suggestions?

Thank you.

Answer 1

It could partially work but this is a bad idea. Just don't do it. Even if it seems to work, it may not. And if it really does, then it will fail randomly in the future.

These are the potential problems that come into my mind:

1. Extensions (those written in C, C++ etc.) are specific to a particular Python version; and numpy has a few extensions, AFAICS. It will work only if you don't use any of them (ie use pure Python modules);
2. Python compiles modules into bytecode. The bytecode is specific to a particular Python version. If you use modules from python2.6 directory in python2.7, the compiled files will collide. I doubt this will cause major problems except for the fact that they will be recompiled every time Python version is switched;
3. Python code can be version-specific. It's unlikely for minor versions (but for example Python 2/3 could have serious differences) but still can happen. In other words, the modules installed for Python2.6 can be actually a bit different than those for Python2.7;
4. If you change the loading order, Python2.7 may start loading some standard modules from Python2.6. it could work, it could cause random breakages;
5. It will make all modules installed for Python2.6 visible. It can cause a few random switches somewhere with unpredictable result. I doubt there's something specific for that version but some modules may actually decide to use some kind of deprecated interface finding it visible.

There could be more. You may actually try but be prepared that you may waste a lot of time trying to find out why something does not work as expected later.

And unless I'm missing something, I think installing numpy for Python2.7 involves mostly running the setup using Python 2.7; like:

python2.7 setup.py clean
python2.7 setup.py build
python2.7 setup.py install

Depending on your particular install/system, it may be preferable to use the package manager, binary bundle or a tool like pip instead. If you'd like more details on how to enforce Python2.7 with those, you'd have to tell us which one is of your choice.