polars-splines: An expression plugin for Polars

A simple extension plugin for polars Python API that uses the Rust cargo splines for spline interpolation.

Installation

Install with pip or uv from PyPI, or build from source with maturin.

Minimal example

import polars as pl
import polars_splines # Adds `spl` to expression namespace

df = pl.DataFrame({"x": [0, 1, 2], "y": [3, 1, 5]})

xi = pl.Series("xi", [0, 0.5, 1.7])

dfi = df.select(
    pl.struct("x", "y").spl.interpolate(xi).alias("yi")
)