ImportError: No module named heaps

Not specified by the original author.

TL;DR: the code needs the standalone heaps package and it is not installed. Run pip install heaps and the import works.

The error

ImportError: No module named heaps

Fix it

1. Install heaps:

   pip install heaps

   Expected: install completes.

2. Verify:

   python -c "import heaps; print('ok')"

   Expected: prints ok.

When this applies

Use this when older graph/assembly tooling (ragout-era code, old networkx-adjacent scripts) raises the heaps error.

When it does not apply

Modern networkx does not need heaps; if modern code raises this, something else is importing it. If the error names a different module, install that one instead.

Compatibility

The heaps package on PyPI; needed by code written against the old pairing-heap API.

Root cause

Years ago some graph tools imported pairing heaps from the standalone heaps package instead of implementing their own. Fresh environments built from incomplete requirements files miss it.

Edge cases

heaps is pure python and installs anywhere. If the real problem is ancient code, consider whether upgrading the tool removes the dependency entirely.

GitHub issue fenderglass/ragout#33 reports ImportError: No module named heaps when importing the tool, which depended on the standalone heaps package for its pairing-heap implementation. The verified fix: installing the heaps package (pip install heaps) provided the missing module and the import succeeded. Full thread: https://github.com/fenderglass/ragout/issues/33