Here is a very good link about how to do it: http://www.rasadacrea.com/en/web-training-courses/howto-install-python

To sum it up:

1. Install the dependencies for python compilation on Ubuntu:

sudo apt-get install build-essential python-dev
sudo apt-get install zlib1g-dev libbz2-dev libcurl4-openssl-dev 
sudo apt-get install libncurses5-dev libsqlite0-dev libreadline-dev 
sudo apt-get install libgdbm-dev libdb4.8-dev libpcap-dev tk-dev 
sudo apt-get -y build-dep python
sudo apt-get -y install libreadline-dev

2. Download and untar the relevant Python version (here 2.7.6):

wget https://www.python.org/ftp/python/2.7.6/Python-2.7.6.tgz
tar xfz Python-2.7.6.tgz

3. cd into the untared Python folder and run the configure and make scripts

cd Python-2.7.6
./configure
make

4. Make alt-install (it is important to make the alt-install and not install so that $python
returns the systsem version (question of stability) )

sudo make altinstall

5. Clean up

cd .. 
sudo rm -r Python-2.7.6*

6. Now you can access to different version of python:

• the one that came originally:

which python
python

• and the one you need for your other needs

which python2.7
python2.7