ambers 0.1.5

Pure Rust SPSS .sav/.zsav reader with Polars DataFrame output

ambers

Pure Rust SPSS .sav/.zsav reader — Arrow-native, zero C dependencies.

Features

• Read .sav (bytecode) and .zsav (zlib) files
• Arrow RecordBatch output — zero-copy to Polars, DataFusion, DuckDB
• Rich metadata: variable labels, value labels, missing values, MR sets, measure levels
• 2–3x faster than pyreadstat
• Python + Rust dual API from a single crate

Installation

Python:

pip install ambers

Rust:

cargo add ambers

Quick Start

Python

import ambers as am

# Read data + metadata
df, meta = am.read_sav("survey.sav")

# Explore metadata
meta.summary()
meta.describe("Q1")
meta.value("Q1")

# Read metadata only (fast, skips data)
meta = am.read_sav_metadata("survey.sav")

Rust

use ambers::{read_sav, read_sav_metadata};

// Read data + metadata
let (batch, meta) = read_sav("survey.sav")?;
println!("{} rows, {} cols", batch.num_rows(), meta.number_columns);

// Read metadata only
let meta = read_sav_metadata("survey.sav")?;
println!("{}", meta.label("Q1").unwrap_or("(no label)"));

Metadata API (Python)

Method	Description
meta.summary()	Formatted overview: file info, type distribution, annotations
meta.describe("Q1")	Deep-dive into a single variable (or list of variables)
meta.diff(other)	Compare two metadata objects, returns MetaDiff
meta.label("Q1")	Variable label
meta.value("Q1")	Value labels dict
meta.format("Q1")	SPSS format string (e.g. "F8.2", "A50")
meta.measure("Q1")	Measurement level ("nominal", "ordinal", "scale")
meta.schema	Full metadata as a nested Python dict

All variable-name methods raise KeyError for unknown variables.

Streaming Reader (Rust)

let mut scanner = ambers::scan_sav("survey.sav")?;
scanner.select(&["age", "gender"])?;
scanner.limit(1000);

while let Some(batch) = scanner.next_batch()? {
    println!("Batch: {} rows", batch.num_rows());
}

Performance

File	Size	Rows	Cols	ambers	pyreadstat	Speedup
survey_medium.sav	147 MB	~22,000	~700	1.27s	3.07s	2.4x
survey_large.sav	1.1 GB	~80,000	~900	2.42s	6.40s	2.6x

License

MIT