A Guide to Python’s Virtual Environments

Well, a virtual environment is just a directory with three important components:

A site-packages/ folder where third party libraries are installed.
Symlinks to Python executables installed on your system.
Scripts that ensure executed Python code uses the Python interpreter and site packages installed inside the given virtual environment.

(venv) % pip freeze
numpy==1.15.3

And write the output to a file, which we’ll call requirements.txt.

(venv) % pip freeze > requirements.txt

Duplicating Environments

Sara% cd test-project/
Sara% python3 -m venv venv/
(venv) Sara% pip install -r requirements.txtCollecting numpy==1.15.3 (from -r i (line 1))
Installing collected packages: numpy
Successfully installed numpy-1.15.3