What does pip install -e .

 

Great question 👌 — pip install -e . is a very common command in Python development, especially when working on local projects or libraries.

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🔍 What it means

• pip install → tells pip to install a package.

• -e (short for --editable) → tells pip to install the package in editable/development mode.

• . → means “install the current directory” (where your setup.py or pyproject.toml file lives).

So, pip install -e . installs your project in editable mode from the current folder.

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⚡ What actually happens

1. Normal install (without -e)

   • Pip builds your package (from setup.py / pyproject.toml).

   • Copies all files into your Python site-packages directory.

   • Any change in your local source files won’t affect the installed version — you’d need to reinstall.

2. Editable install (-e)

   • Instead of copying, pip creates a link (symlink or .egg-link) from site-packages back to your source directory.

   • Your project’s metadata (.egg-info or .dist-info) is still created in site-packages.

   • Now, when you import the package, Python loads directly from your source folder.

   ✅ This means any changes you make to the code locally are immediately reflected without reinstalling.

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🛠 Typical use cases

• Developing your own Python package and testing changes quickly.

• Contributing to an open-source library and wanting to run it locally.

• Avoiding repeated re-installation during active development.

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📌 Example

Suppose your project looks like this:

myproject/
├── setup.py
├── pyproject.toml
└── mypackage/
    └── __init__.py

Run:

pip install -e .

• Your package mypackage is now importable anywhere (e.g., import mypackage).

• Any edits you make to mypackage/__init__.py will be reflected immediately when you re-run Python.

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👉 Would you like me to also explain how pip install -e . works with pyproject.toml-based projects (PEP 517/518) since many modern projects no longer use setup.py?