no module named zlib

Question

First, please bear with me. I have hard time telling others my problem and this is a long thread...

I am using pythonbrew to run multiple versions of python in Ubuntu 10.10. For installing pythonbrew and how it works, please refers to this link below

http://www.howopensource.com/2011/05/how-to-install-and-manage-different-versions-of-python-in-linux/

After reading a couple stackoverflow threads, I finally found the file called Setup under this directory: ~/.pythonbrew/pythons/Python-2.7.1/lib/python2.7/config

In this Setup file I see 
# Andrew Kuchling's zlib module.
# This require zlib 1.1.3 (or later).
# See http://www.gzip.org/zlib/
# zlib zlibmodule.c -I$(prefix)/include -L$(exec_prefix)/lib -lz

I uncommented the last line, then I ran python -v again. However, I received the same error when I tried import zlib, so I guess I have to do something to install zlib into the lib.

But I am clueless about what I need to do. Can someone please direct me in the right direction??? Thank you very much!

I am doing this because I want to use different version of python in different virtualenv I created. When I did virtualenv -p python2.7 I received no module named zlib.

jwxie518@jwxie518-P5E-VM-DO:~$ virtualenv -p python2.7 --no-site-packages testenv

Running virtualenv with interpreter /home/jwxie518/.pythonbrew/pythons/Python-2.7.1/bin/python2.7

Traceback (most recent call last):
  File "/usr/local/lib/python2.6/dist-packages/virtualenv.py", line 17, in <module>
    import zlib

ImportError: No module named zlib

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EDIT

I have to install 2.7.1 by appending --force.

I am developing Django, and I need some of these missing modules, for example sqlite3, and to create my virtualenv I definitely need zlib. If I just use the system default (2.6.6), I have no problem.

To do this with system default, all I need to do is

virtualenv --no-site-packages testenv

Thanks!

---

(2nd edit)

I installed 3.2 also and I tested it without problem, so I guess my problem comes down to how to install the missing module(s).

jwxie518@jwxie518-P5E-VM-DO:~$ virtualenv -p python3.2  testenv
Running virtualenv with interpreter /home/jwxie518/.pythonbrew/pythons/Python-3.2/bin/python3.2
New python executable in testenv/bin/python3.2
Also creating executable in testenv/bin/python
Installing distribute..................................................................................................................................................................................................................................................................................................................................done.
Installing pip...............done.
jwxie518@jwxie518-P5E-VM-DO:~$ virtualenv -p python3.2 --no-site-packages testenv
Running virtualenv with interpreter /home/jwxie518/.pythonbrew/pythons/Python-3.2/bin/python3.2
New python executable in testenv/bin/python3.2
Also creating executable in testenv/bin/python
Installing distribute..................................................................................................................................................................................................................................................................................................................................done.
Installing pip...............done.

Answer 1

Sounds like you need to install the devel package for zlib, probably want to do something like sudo apt-get install zlib1g-dev (I don't use ubuntu so you'll want to double-check the package). Instead of using python-brew you might want to consider just compiling by hand, it's not very hard. Just download the source, and configure, make, make install. You'll want to at least set --prefix to somewhere, so it'll get installed where you want.

./configure --prefix=/opt/python2.7 + other options
make
make install

You can check what configuration options are available with ./configure --help and see what your system python was compiled with by doing:

python -c "import sysconfig; print sysconfig.get_config_var('CONFIG_ARGS')"

The key is to make sure you have the development packages installed for your system, so that Python will be able to build the zlib, sqlite3, etc modules. The python docs cover the build process in more detail: http://docs.python.org/using/unix.html#building-python.