ImportError: cannot import name RangeIndex

TL;DR: your fastparquet is too old for your pandas. pandas removed RangeIndex from pandas.core.index, so upgrade fastparquet to a compatible release, or pin an older pandas.

The error

ImportError: cannot import name RangeIndex

Fix it

1. Upgrade fastparquet:

   pip install -U fastparquet

   Expected: installs a release that imports RangeIndex from the right place.

2. Verify:

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

   Expected: imports cleanly.

3. Workaround if you cannot upgrade fastparquet: pin pandas to a version that still has the old path:

   pip install "pandas<1.0"

   Expected: the old import path works again.

When this applies

Use this when import fastparquet raises the RangeIndex error with a modern pandas.

When it does not apply

If your own code imports RangeIndex from pandas.core.index, use pandas.RangeIndex instead. If fastparquet is current, reinstall it.

Compatibility

Old fastparquet with pandas 1.0+. pandas.RangeIndex is the stable public path on all pandas versions.

Root cause

pandas reorganized its internals and removed the pandas.core.index alias for RangeIndex. fastparquet imported the internal path, so the removal broke it at import time.

Edge cases

Pinning ancient pandas breaks most of the modern stack; upgrading fastparquet is strongly preferred. The same pandas-internal cleanup broke other old libraries the same way.

GitHub issue dask/fastparquet#269 reports ImportError: cannot import name RangeIndex when importing fastparquet, with the traceback showing from pandas.core.index import RangeIndex, Index. The verified answer: newer pandas removed RangeIndex from pandas.core.index, so old fastparquet broke; the fix is upgrading fastparquet to a release compatible with the installed pandas (or pinning an older pandas as a workaround). Full thread: https://github.com/dask/fastparquet/issues/269