numbarrow

Numba adapters for PyArrow and PySpark.

numbarrow lets you work with Apache Arrow arrays directly inside Numba @njit compiled functions. It converts PyArrow arrays into NumPy views (zero-copy where possible) and extracts validity bitmaps for null handling — bridging PySpark's Arrow-based batch processing with high-performance JIT-compiled code.

Installation

pip install numbarrow

Optional dependencies for PySpark and pandas support:

pip install numbarrow[test]       # adds pyspark
pip install numbarrow[mapinarrow] # adds pandas

Quick Start

import pyarrow as pa
from numba import njit
from numbarrow.core.adapters import arrow_array_adapter
from numbarrow.core.is_null import is_null

# Convert a PyArrow array to NumPy for use in @njit
arrow_array = pa.array([10, None, 30, 40], type=pa.int32())
bitmap, data = arrow_array_adapter(arrow_array)

@njit
def sum_non_null(data, bitmap):
    total = 0
    for i in range(len(data)):
        if bitmap is None or not is_null(i, bitmap):
            total += data[i]
    return total

result = sum_non_null(data, bitmap)  # 80

Supported Types

PyArrow Type	NumPy Result	Copy?
Int32Array, Int64Array, DoubleArray	Matching dtype	No (view)
BooleanArray	bool_	Yes (bit-unpacking)
Date32Array	datetime64[D]	Yes (int32 → int64)
Date64Array	datetime64[ms]	No (view)
TimestampArray	datetime64[unit]	No (view)
StringArray	Fixed-width Unicode (bitmap not returned)	Yes (repacking)
StructArray	Tuple of two dicts: (bitmaps, data) per field	Per-field
ListArray (of structs)	Tuple of two dicts: (bitmaps, data) per field	Per-field

PySpark Integration

Use make_mapinarrow_func to create functions compatible with PySpark's mapInArrow:

from numbarrow.core.mapinarrow_factory import make_mapinarrow_func

def compute(data_dict, bitmap_dict, broadcasts):
    # data_dict: {col_name: np.ndarray}
    # bitmap_dict: {col_name: uint8 bitmap array}
    result = data_dict["value"] * broadcasts["scale"]
    return {"output": result}

udf = make_mapinarrow_func(compute, broadcasts={"scale": 2.0})
df_out = df_in.mapInArrow(udf, output_schema)

See test/demo_map_in_arrow.py for a complete runnable example.

Compatibility

Dependency	Versions
Python	3.10 – 3.12
numba	0.60 – 0.63
pyarrow	14 – 18
pyspark	3.3 – 3.x (optional)
pandas	1.5+ (optional)

Documentation

Full API documentation: numbarrow docs

License

See LICENSE.