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Why do I need a requirements.txt file?

The requirements.txt has two major benefits.

  1. It tells other developers which libraries your application needs.

  2. Instead of installing libraries one by one, you can install them all at once with:

# bash

$ pip install -r requirements.txt

Tutorial

  1. Create a new project folder

For this tutorial, we’ll call it python_requirements, but you can name it anything.

  1. Change into the new project directory, install a new virutal environment, and activate it.
# bash

$ cd python_requirements
$ python -m venv venv
# Mac and Linux
$ source venv/bin/activate
# Windows users run a different command
$ .\bubble\Scripts\activate
  1. Install the following libraries using pip.
# bash

$ pip install pyjokes
$ pip install quoters
$ pip install random_word
  1. Create a new app called app.py and import the three libraries into the app.

I’m going to use nano for this example but you could easily use an IDE like VS Code.

# bash

$ nano app.py

# python

from quoters import Quote
from random_word import RandomWords
import pyjokes

print("hello")

Create requirments.txt the standard way

  1. In a terminal within the project/app directory run the command:
# bash

pip freeze > requirements.txt

This command will add all the libraries to the requirements.txt. From the imported libraries used to the dependencies, etc.

Only used libraries requirements.txt (alternative)

  1. Install the library pipreqs
# bash

$ pip install pipreqs
  1. The run the command:
# bash

# if you are in the project directory, then just run pipreqs
$ pipreqs /path/to/your/project

# for this project, I was in the project directory so I ran:
$ pipreqs
  1. Running this command will generate the requirements.txt with only the libraries imported / used in the project.
# bash

pyjokes==0.8.3
quoters==0.30
random_word==1.0.13

🎉 Congrats

You now know how to generate a requirements.txt which will help with future personal and team projects.