All 15 Modules & Packaging questions
More in Modules & Packaging
What is __all__ and how does it control `from module import *` behavior? What is the purpose of a `requirements.txt` file, and how does it differ from dependency declarations in pyproject.toml? What does 'editable install' (pip install -e .) mean, and why is it useful during development? How does Python locate modules during import, and what is sys.path's role? How does Python resolve circular imports, and what strategies avoid the resulting ImportError? How does importlib let you dynamically import a module by name at runtime? How do entry points in packaging metadata enable a package to register CLI commands or plugins? How does the module search and caching system handle submodule imports like `import package.subpackage.module`?
Advertisement
Python › Modules & Packaging

What is a namespace package, and how does it differ from a regular package?

Advanced

Answer

A namespace package (PEP 420) is a package without an __init__.py that can span multiple directories or distributions -- Python implicitly recognizes any directory containing Python files as a namespace package portion, letting a single logical package (like `myorg.tools`) be split across separately installed distributions that merge into one importable namespace at runtime.
# No __init__.py needed:
# dist1/myorg/tools/a.py
# dist2/myorg/tools/b.py
# Both contribute to the same 'myorg.tools' namespace package

import myorg.tools.a
import myorg.tools.b
Real-world example A large organization splits a monorepo's internal tooling into separately versioned pip packages (myorg-tools-network, myorg-tools-storage) that all contribute submodules to the same `myorg.tools` namespace.

Common follow-ups: What are the downsides of namespace packages regarding import speed?;How do you explicitly declare a regular package to avoid ambiguity?

Virtual Environments & Dependency Management;Modules & Packaging
All 15 Modules & Packaging questions