ImportError: No module named decorator

Not specified by the original author.

TL;DR: networkx requires the decorator package and it is not installed. Run pip install decorator and networkx imports fine.

The error

ImportError: No module named decorator

Fix it

1. Install decorator:

   pip install decorator

   Expected: install completes.

2. Verify:

   python -c "import networkx; print(networkx.__version__)"

   Expected: prints the version, no error.

When this applies

Use this when import networkx raises the decorator error, common after --no-deps installs.

When it does not apply

If decorator is installed but networkx still fails, check for a broken install with pip check. If the error names a different module, install that one instead.

Compatibility

All networkx 2.x versions; decorator has always been required.

Root cause

networkx uses the decorator package for its decorator-heavy API (notable edge-attribute decorators). The dependency is declared, but installs that skip dependencies leave it out.

Edge cases

Very old decorator versions can break new networkx; installing normally gets a compatible one. In conda envs, install decorator from the same channel as networkx.

GitHub issue networkx/networkx#2014 reports ImportError: No module named decorator when importing networkx. The verified fix: decorator is a hard dependency of networkx that was missing from the environment, so installing it with pip install decorator resolved the import. Full thread: https://github.com/networkx/networkx/issues/2014