pandas_numba

A tiny numba jitclass holding pandas-style typed columns for use inside @njit nopython code — plus a pandas DataFrame bridge and objmode glue to call back into pandas from jitted code.

Repository: https://github.com/quantaiko/Pandas_numba

• Pandas_nb — a jitclass DataFrame-like container: one numpy array per column, keyed by title, one typed dict per element type.
• f_df_to_nb / f_nb_to_df (and friends) — the pandas bridge, module-level functions: DataFrame → Pandas_nb and back, with columns shared as views where possible.
• f_eval_expr + objmode — carry a DataFrame by handle and run pandas on the live frame from inside @njit.

Requirements

• Python 3.12
• numpy, pandas, numba

Quick start

import pandas as pd
from numba import njit
from pandas_numba import f_df_to_nb, f_nb_to_np

df = pd.DataFrame({"a": [1., 2., 3.], "b": [1, 2, 3]}) # small dataframe
pandas_nb = f_df_to_nb(df)                          # columns shared as views

@njit
def f_update(pandas_nb):
    pandas_nb.m_floats["a"][:] = pandas_nb.m_floats["a"] * 2   # df will be changed (shared view)
    pandas_nb.f_add_int("c", pandas_nb.m_ints["b"] + 10)      # new int column (built in nopython)

f_update(pandas_nb)                     # run in nopython mode
df["c"] = f_nb_to_np(pandas_nb, "c")    # copy the new column back into df
print(df)                               # df is changed
#      a  b   c
# 0  2.0  1  11
# 1  4.0  2  12
# 2  6.0  3  13

(The same script lives in simple_example.py.)

Example data

simple_case_study.py generates a small top-of-book order-book DataFrame (bid/ask prices and volumes over time) as a worked example to feed through the bridge functions. f_make_book(n) scales it to n rows.

Documentation

See pandas_numba.md for the full data model, API, the pandas round-trip rules, the df-by-handle / string-eval objmode mechanism, and the numba constraints.

Tests

python -m pytest pandas_numba_tests.py -v

The suite is driven by one ALL_TYPES table — add a column type by adding one row and every per-type test covers it.

License

MIT © 2026 Damien Loison