Creating and using Python Virtual Environments
In a lot of my courses I encourage students to use python virtual environments. Virtual environments are a great way of making sure that you have the correct version of packages installed. This is very short cheat sheet on how to set them up. I will assume that we are using Python 3. Luckily Python 3 has virtual environments set up. It is all in the documentation, but then sometimes people are too lazy to google, or do not know what to google for. Of course this assumes that you are a command line person. If you are using some IDE, then you are on your own.
To create a virtual environment in the current directory do the following
python3 -m venv env
If you look in the directory you'll see a sub-directory env
this
contains all files that drive the virtual environment. In particular
there is a sub-directory env/bin/
Justins-MacBook-Air-2:Example justin$ ls env/bin/
Activate.ps1 easy_install pip3.9
activate easy_install-3.9 python
activate.csh pip python3
activate.fish pip3 python3.9
The most important file is the activate
script. To start your
virtual environment you simply do
source ./env/bin/activate
This executes the activate script. Notice that you prompt has changed
to (env)
You are now free to install what ever packages want. For exampe
pip3 install panda
pip3 install numpy
Once you have done all your Python goodness you should leave your virtual environment.
(env) Justins-MacBook-Air-2:Example justin$ deactivate