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I have default python 2.7 and i try to install python3.3 and install pip3 and Django.now when i try to install others using yum i got this error.for a example yum update

There was a problem importing one of the Python modules required to run yum. The error leading to this problem was: No module named yum Please install a package which provides this module, or verify that the module is installed correctly. It's possible that the above module doesn't match the current version of Python, which is: 2.7.5 (default, Nov 12 2013, 16:18:42) [GCC 4.8.2 20131017 (Red Hat 4.8.2-1)] If you cannot solve this problem yourself, please go to the yum faq at: http://yum.baseurl.org/wiki/Faq

How can i fix this error?

Nuwan Indika
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    You should not change the system python. `yum` relies on it. If you install a new python, put it in an alternative path. You can then use `virtualenv` to use the new python seamlessly. – juanchopanza May 11 '14 at 07:20
  • check here: http://stackoverflow.com/questions/10624511/upgrade-python-without-breaking-yum – mortymacs May 11 '14 at 11:14

2 Answers2

19

There is probably many python versions on your system and only one of them has the yum library installed. For some reason the python binary called when you run yum on the command line is not the one who has the yum library installed.

Find the list of python 2 binaries available on your system. Run as root:

find / -type f -executable -name 'python2*'

The output will probably look like that:

/usr/bin/python2.6
/usr/bin/python2.7
...

etc...

For each one of these, run

/usr/bin/python2.x

You'll get a python prompt. Run:

>>> import yum

Do this for every python binary until you find one that doesn't raise an ImportError at this step.

Then find out what is the path that yum is using to run python. This is the first line in the yum script. Run

cat `which yum` | head -1

You'll probably get:

#!/usr/bin/python

Now, run as root:

ln -s /usr/bin/python2.x /usr/bin/python

(replace python2.x with the good python version you found earlier).

John Smith Optional
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  • You are right. But I need to use python2.7 instead of python2.6. How to make python2.7 the default python version? – Gank Dec 28 '14 at 06:19
  • That's the purpose of the `ln -s /usr/bin/python2.x /usr/bin/python` command I wrote in my answer. Replace /usr/bin/python2.x with the location of the python2.7 on your system. If it's not /usr/bin/python2.7, run `which python2.7` to find out where it is. – John Smith Optional Dec 28 '14 at 10:11
  • Of course, do this only if python2.7 is really supposed to be the default python on your system. If python2.6 is the python version officially supported by your distro, you should keep it that way. Just run `python2.7 myapp.py` when you want to run an app with python2.7. – John Smith Optional Dec 28 '14 at 10:28
  • Yes. Then I can't use easy_install or pip any more, everytime I use python2.7 setup.py install – Gank Dec 28 '14 at 12:11
2

I have the same problem.

Yum has been written in Python lang.

So when you upgrade your default Python to new version it will make problem for yum. If you get python --version it will tell you 3.3.

For solving this problem , change python command to python2.7.

First check it:

user@host:~$ ls -l /usr/bin/python
lrwxrwxrwx 1 root root 9 Sep 28  2013 /usr/bin/python -> python3.3

Try it:

mv /usr/bin/python /usr/bin/python-origin
ln -s python2.7 /usr/bin/python

Then check it:

user@host:~$ ls -l /usr/bin/python
lrwxrwxrwx 1 root root 9 Sep 28  2013 /usr/bin/python -> python2.7

If you wish to install python3 in CentOS you should install that via source code.

download main source code via python.org website.
extract archive file.
./configure
make
make install
mortymacs
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