Why requirements.txt?
Any application typically has a set of dependencies that are required for that application to work. The requirements file is a way to specify and install specific set of package dependencies at once.
Format for requirements file:
requests==1.2.0 Flask==0.10.1
Method 1:
$ pip freeze > requirements.txt
Use pip’s freeze command to generate a requirements.txt file for your project: If you save this in requirements.txt, then you can pip install -r requirements.txt.
Method 2:
Use pipreqs – pipreqs used to generate requirements.txt file for any project based on imports
Why not pip freeze ?
pip freeze saves all packages in the environment including those that you don’t use in your current project. (if you don’t have virtualenv)
pip freeze only saves the packages that are installed with pip install in your environment.
sometimes you just need to create requirements.txt for a new project without installing modules.
How to use?
$ pip install pipreqs $ pipreqs /path/to/project
for additional options see https://github.com/bndr/pipreqs