fp-index

Flat and multi-level row-index types (Index, MultiIndex) for pandas-parity dataframes.

Part of the frankenpandas workspace.

When to depend on fp-index directly

Most users should depend on the umbrella frankenpandas crate instead. Direct dependency makes sense when:

• Building a library that needs pandas-style row-axis identity / alignment without the full DataFrame machinery.
• Implementing a custom DataFrame that reuses frankenpandas's index primitives.

Key types

• Index — flat row index over IndexLabel values (Int64, Utf8, Timedelta64, Datetime64).
• MultiIndex — hierarchical row index with level arrays + optional level names. Supports from_tuples, from_arrays, from_product, get_level_values, droplevel, swaplevel, reorder_levels, to_flat_index.
• MultiIndexOrIndex — shape-polymorphic accessor returning the logical row axis as either variant.
• Alignment algebra via AACE (AG-01..05 leapfrog triejoin) used by fp-join and fp-frame arithmetic.

Status

Foundation stable. Row MultiIndex integration into fp-frame's DataFrame row axis landed via br-frankenpandas-1zzp (closed 2026-04-22).

Links

• Workspace README
• CHANGELOG