sparkless 4.9.0

PySpark-like DataFrame API in Python—no JVM. Uses robin-sparkless (Rust/Polars) as the execution engine.

Robin Sparkless

PySpark-style DataFrames in Python—no JVM. Install the sparkless package for a drop-in local PySpark replacement (fast unit tests + CI, no Java/Spark). Under the hood it’s powered by the robin-sparkless Rust engine using Polars for execution.

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Quick start (Python)

# Swap the import—everything else stays the same.
from sparkless.sql import SparkSession, functions as F

spark = SparkSession.builder.app_name("demo").get_or_create()
df = spark.createDataFrame([{"x": 1}, {"x": 2}])
df.filter(F.col("x") > 1).show()

Install from PyPI:

pip install "sparkless>=4,<5"

More Python docs (SQL/temp views, Delta, JDBC, testing plugin): see python/README.md.

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Why Sparkless (Python)?

• Familiar API — SparkSession, DataFrame, Column, and PySpark-like functions so you can reuse patterns without the JVM.
• Fast local execution — Runs natively (no JVM) and uses Polars for IO, expressions, and aggregations.
• Test the same suite two ways — Use sparkless.testing to run tests with Sparkless (fast) or real PySpark (parity checks).
• Optional “Spark-like” features — SQL, temp/global temp views, saveAsTable, Delta, and JDBC (see python/README.md).

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Features (Python surface)

Area	What’s included
Core	SparkSession, DataFrame, Column, functions
IO	CSV, Parquet, JSON, Delta
Expressions	col, lit, when/otherwise, casts, null handling
Aggregates	count, sum, avg, min, max, groupBy().agg()
Window	row_number, rank, dense_rank, lag, lead, first_value, last_value via .over()
Arrays, strings, JSON	Common PySpark functions (explode, regexp_*, get_json_object, from_json, to_json, …)
SQL + views	spark.sql, temp/global temp views, saveAsTable, catalog().listTables()
JDBC	Read/write via spark.read.jdbc(...) / df.write.jdbc(...)

Parity: 200+ fixtures validated against PySpark. Known differences: docs/PYSPARK_DIFFERENCES.md. Full parity status: docs/PARITY_STATUS.md. Out-of-scope items: docs/DEFERRED_SCOPE.md.

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Installation

Python (sparkless v4)

Install from PyPI:

pip install "sparkless>=4,<5"

Or from this repo:

pip install ./python

See python/README.md for usage and development (including maturin develop).

Rust engine (optional)

Most users should use the Python package above. If you want to embed the engine directly in Rust, depend on robin-sparkless.

Add to your Cargo.toml:

[dependencies]
robin-sparkless = "4"

Optional features:

robin-sparkless = { version = "4", features = ["sql"] }      # spark.sql(), temp views
robin-sparkless = { version = "4", features = ["delta"] }    # Delta Lake read/write
robin-sparkless = { version = "4", features = ["jdbc"] }     # PostgreSQL JDBC
robin-sparkless = { version = "4", features = ["sqlite"] }   # SQLite JDBC
robin-sparkless = { version = "4", features = ["jdbc_mysql"] } # MySQL/MariaDB JDBC

Development

If you’re working on the Python package, start in python/README.md (it covers maturin develop, pytest, and dual-mode testing).

If you’re working on the Rust engine crates, see docs/QUICKSTART.md and the crate READMEs in crates/.

This repository contains:

• python/: the sparkless Python package (v4)
• Rust crates: the robin-sparkless engine (Cargo workspace)

Command	Description
pip install ./python	Install the Python package from this repo
cd python && maturin develop	Editable install for Python development
pytest tests/ -v	Run Python tests (sparkless backend)
SPARKLESS_TEST_MODE=pyspark pytest tests/ -v	Run the same tests against real PySpark
scripts/typecheck_strict.sh	Strict mypy for the Python sparkless package
make check	Rust engine: format, clippy, audit/deny, Rust tests
make test-parity-phases	Run PySpark parity fixtures (Rust engine)

CI runs format, clippy, audit, deny, Rust tests, and parity tests on push/PR (see .github/workflows/ci.yml).

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Documentation

Resource	Description
Python package	Sparkless v4 — install from PyPI (pip install sparkless) or pip install ./python, quick start, Sparkless 3 vs 4.x, API overview
Read the Docs	Full docs: quickstart, Rust usage, Python getting started, Sparkless integration (MkDocs)
docs.rs	Rust API reference
QUICKSTART	Build, usage, optional features, benchmarks
User Guide	Everyday usage (Rust)
Persistence Guide	Global temp views, disk-backed saveAsTable
UDF Guide	Scalar, vectorized, and grouped UDFs
Testing Guide	Dual-mode testing with sparkless.testing
PySpark Differences	Known divergences
Roadmap	Development phases, Sparkless integration
RELEASING	Publishing to crates.io and PyPI

See CHANGELOG.md for version history.

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License

MIT