Python

What is the use of __pycache__?

The __pycache__ directory is automatically created by Python to store compiled bytecode files (.pyc files) when you import modules. Here's what you need to know:

  1. Purpose:
  • Speeds up subsequent imports of the same module
  • Contains pre-compiled bytecode (optimized intermediate format) instead of re-parsing source code every time
  1. Characteristics:
  • Files are named like module.cpython-310.pyc (includes Python version)
  • Automatically regenerated when source files change
  • Typically excluded from version control (add to .gitignore)
  1. When it's created:
my_project/
├── __pycache__/          # Auto-generated
│   └── module.cpython-310.pyc
└── module.py             # Your source file
  1. Best practices:
  • Don't commit these files to Git
  • Safe to delete (Python will regenerate them)
  • Helps performance in multi-import scenarios

You can disable bytecode caching by running Python with the -B flag: