What I did to get Python 3.4.2 on Ubuntu 14.04. The stock version of Python 3 on Ubuntu is 3.4.0. Which is missing some of the best parts! (asyncio, etc). Luckily I discovered pyenv which solved my problem.
Pyenv (not to be confused with pyvenv) is the Python equivelant of rbenv. It lets you configure which Python environment/version is available per directory, user, or other session variables.
I followed the instructions here to install pyenv in my home directory. Verbatim, those instructions are:
sudo apt-get install git python-pip make build-essential libssl-dev zlib1g-dev libbz2-dev libreadline-dev libsqlite3-dev
sudo pip install virtualenvwrapper
git clone https://github.com/yyuu/pyenv.git ~/.pyenv
git clone https://github.com/yyuu/pyenv-virtualenvwrapper.git ~/.pyenv/plugins/pyenv-virtualenvwrapper
echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bashrc
echo 'export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(pyenv init -)"' >> ~/.bashrc
echo 'pyenv virtualenvwrapper' >> ~/.bashrc
Restart your shell to pickup pyenv. Then tell pyenv to download, build, and instatll 3.4.2:
pyenv install 3.4.2
Place a hidden file .python-version in your project. In this file simply place the text:
3.4.2
In this directory, type python to enter the shell and note the version. It should be 3.4.2.
You should also now be able to use pyvenv to bootstrap a virtual environment in this directory. It will bootstrap a virtualenv with python 3.4.2 as the python version. You can do everything you'd normally do in a virtualenv, like install dependencies, etc:
pyvenv venv
source venv/bin/activate
pip install requests
pip freeze > requirements.txt
I use pyflakes with Syntastic for finding syntax bugs in VIM. I had to be sure to install pyflakes to python 3.4.2 by going into a directory where 3.4.2 was being used and doing
pip install pyflakes
Edited to correct spelling. I changed "Verbatem" to "Verbatim" after I noticed it was misspelled,or misspelt if you prefer British English.