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

---

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

After you install the missing zlib dev package you can also use pythonbrew to uninstall and then reinstall the version of python you wanted and it seems like it picks up the new package to compile to correct abilities. This way you can keep using pythonbrew and don't have to do the compilation yourself (though it isn't that difficult)

Answer 2

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.

Answer 3

I had a lot of problems making a virtual environment (venv) as described in the tensorflow installation guide.

Most of the commands listed in this post didn't help me either so, if this is also your case this is what I did:

1. pip3 install --user pipenv
2. pip install virtualenv

Installs the dependencies to create a virtual environment

3. mkdir myenv

Makes a new directory called myenv but you can call it whatever you want e.g. mynewenv

4. cd myenv

Or whatever you call your directory so: cd [your_directory_name]

5. virtualenv -p /usr/bin/python3 venv

Creates a virtual environment called venv in the folder myenv. You can call your virtual env whatever you like e.g. vitualenv [v_env_name]

6. source ./venv/bin/activate

Activates the virtual environment. Note that if you choose a different v. env. name your commands should be written as such source ./[v_env_name]/bin/activate

7. deactivate

Deactivates the virtual environment.

Note: I am using Python 3.6.6 & Ubuntu 18.04

source for the commands

Answer 4

By default when you configuring Python source, zlib module is disabled, so you can enable it using option --with-zlib when you configure it. So it becomes

./configure --with-zlib

Answer 5

My objective was to create a new Django project from the command line in Ubuntu, like so:

django-admin.py startproject mysite

I have python2.7.5 installed. I got this error:

ImportError: No module named zlib

For hours I could not find a solution, until now!

Here is a link to the solution -

http://doc.biblissima-condorcet.fr/loris-setup-guide-ubuntu-debian

I followed and executed instruction in Section 1.1 and it is working perfectly! It is an easy solution.

Answer 6

The easiest solution I found, is given on python.org devguide:

sudo apt-get build-dep python3.6

If that package is not available for your system, try reducing the minor version until you find a package that is available in your system’s package manager.

I tried explaining details, on my blog.