Python Virtual environments

The use of a Virtual Environment is to test python code in encapsulated environments, and to also avoid filling the base Python installation with libraries we might use for only one project.

virtualenv

1. Install virtualenv

   pip install virtualenv
   

2. Install virtualenvwrapper-win (Windows)

   pip install virtualenvwrapper-win
   

Usage:

1. Make a Virtual Environment named HelloWorld

   mkvirtualenv HelloWorld
   

   Anything we install now will be specific to this project. And available to the projects we connect to this environment.

2. Set Project Directory

   To bind our virtualenv with our current working directory we simply enter:

   setprojectdir .
   

3. Deactivate

   To move onto something else in the command line type deactivate to deactivate your environment.

   deactivate
   

   Notice how the parenthesis disappear.

4. Workon

   Open up the command prompt and type workon HelloWorld to activate the environment and move into your root project folder

   workon HelloWorld
   

Poetry

1. Install Poetry

   pip install --user poetry
   

2. Create a new project

   poetry new my-project
   

   This will create a my-project directory:

   my-project
   ├── pyproject.toml
   ├── README.rst
   ├── poetry_demo
   │   └── __init__.py
   └── tests
       ├── __init__.py
       └── test_poetry_demo.py
   

   The pyproject.toml file will orchestrate your project and its dependencies:

   [tool.poetry]
   name = "my-project"
   version = "0.1.0"
   description = ""
   authors = ["your name <your@mail.com>"]
   
   [tool.poetry.dependencies]
   python = "*"
   
   [tool.poetry.dev-dependencies]
   pytest = "^3.4"
   

3. Packages

   To add dependencies to your project, you can specify them in the tool.poetry.dependencies section:

   [tool.poetry.dependencies]
   pendulum = "^1.4"
   

   Also, instead of modifying the pyproject.toml file by hand, you can use the add command and it will automatically find a suitable version constraint.

   $ poetry add pendulum
   

   To install the dependencies listed in the pyproject.toml:

   poetry install
   

   To remove dependencies:

   poetry remove pendulum
   

For more information, check the documentation or read here:

• Python projects with Poetry and VSCode. Part 1
• Python projects with Poetry and VSCode. Part 2
• Python projects with Poetry and VSCode. Part 3

Pipenv

1. Install pipenv

   pip install pipenv
   

2. Enter your Project directory and install the Packages for your project

   cd my_project
   pipenv install <package>
   

   Pipenv will install your package and create a Pipfile for you in your project’s directory. The Pipfile is used to track which dependencies your project needs in case you need to re-install them.

3. Uninstall Packages

   pipenv uninstall <package>
   

4. Activate the Virtual Environment associated with your Python project

   pipenv shell
   

5. Exit the Virtual Environment

   exit
   

Find more information and a video in docs.pipenv.org.

Anaconda

Usage:

1. Make a Virtual Environment

   conda create -n HelloWorld
   

2. To use the Virtual Environment, activate it by:

   conda activate HelloWorld
   

   Anything installed now will be specific to the project HelloWorld

3. Exit the Virtual Environment

   conda deactivate