Python Virtual Environments

January 08, 2020

What is a virtual environment

The main purpose of virtual environments is to create isolated environments for Python projects. As such, each project can have its own dependencies, regardless of the dependencies in other projects or on your ‘main’ PC.

Setup a virtual environment

Installing a virtual environment is pretty easy. First, use pip3 (for Python3) to install the package.

WAUTERW-M-65P7:Parse_YAML_Python wauterw$ pip3 install virtualenv

Next, create a virtual environment:

WAUTERW-M-65P7:Parse_YAML_Python wauterw$ python3 -m venv
usage: venv [-h] [--system-site-packages] [--symlinks | --copies] [--clear] [--upgrade] [--without-pip]
            [--prompt PROMPT]
            ENV_DIR [ENV_DIR ...]

The above learns us that the main command is python3 -m venv, but we also need to give the virtual environment a name. Most people use venv as the name, but this is entirely up to you. In any case, it explains a bit why you see two times the word venv in below command.

WAUTERW-M-65P7:Parse_YAML_Python wauterw$ python3 -m venv venv

Next, we need to activate the virtual environment:

WAUTERW-M-65P7:Parse_YAML_Python wauterw$ source venv/bin/activate
(venv) WAUTERW-M-65P7:Parse_YAML_Python wauterw$

Observe that the command prompt now has this (venv) statement in front of it. This means you are into the virtual environment. Any install request under that virtual environment is entirely isolated from other environments.

Short post, hope you enjoyed it!