Python Virtual Environment - Nikola Andrić Notes

Python virtual environment is a self-contained directory tree that includes a Python installation and number of additional packages.

The main purpose of Python virtual environments is to create an isolated environment for different Python projects. This way you can install a specific version of a module on a per project basis without worrying that it will affect your other Python projects.

Steps:

Install the package that provides the venv module
```
 sudo apt install python3-venv
```
Switch to the directory where you want to create your virtual environment and execute the following command that will create a virual environment called my_project_venv that will contain a copy of the Python binary, the pip package manager, the standard Python library and other packets:
```
 python3 -m venv my_project_venv
```
To start using this environment, run the activate script:
```
 source my_project_venv/bin/activate
```
Once you are done with your work to deactivate the environment, simply type deactivate and you will return to your normal shell.
```
 deactivate
```

Steps for reinstalling all dependencies into another environment:

Create a requirements.txt with all dependencies using the following command:
```
  pip freeze > requirements.txt
```
Copy this file to the other machine and install all dependencies using the following command:
```
  pip install -r requirements.txt
```

Conda Python Environment

Create the environment:

  conda create --name my_project_venv python=3.6

Activate the environment:
```
  activate my_project_venv         
```

Nikola Andrić