pandrs 0.1.0

A high-performance DataFrame library for Rust, providing pandas-like API with advanced features including SIMD optimization, parallel processing, and distributed computing capabilities
Documentation
# PandRS

[![Crate](https://img.shields.io/crates/v/pandrs.svg)](https://crates.io/crates/pandrs)
[![License: MIT OR Apache-2.0](https://img.shields.io/badge/License-MIT%20OR%20Apache--2.0-blue.svg)](https://opensource.org/licenses/MIT)
[![Documentation](https://docs.rs/pandrs/badge.svg)](https://docs.rs/pandrs)

A high-performance DataFrame library for Rust, providing pandas-like API with advanced features including SIMD optimization, parallel processing, and distributed computing capabilities.

> **🚀 Version 0.1.0 - Production Ready**: PandRS is ready for production use with comprehensive quality improvements. With 1334+ tests, zero clippy warnings, enhanced documentation, and optimized performance, PandRS delivers a robust pandas-like experience for Rust developers. Published to crates.io December 2025.

## Overview

PandRS is a comprehensive data manipulation library that brings the power and familiarity of pandas to the Rust ecosystem. Built with performance, safety, and ease of use in mind, it provides:

- **Type-safe operations** leveraging Rust's ownership system
- **High-performance computing** through SIMD vectorization and parallel processing
- **Memory-efficient design** with columnar storage and string pooling
- **Comprehensive functionality** matching pandas' core features
- **Seamless interoperability** with Python, Arrow, and various data formats

## Quick Start

```rust
use pandrs::{DataFrame, Series};
use std::collections::HashMap;

// Create a DataFrame
let mut df = DataFrame::new();
df.add_column("name".to_string(), 
    Series::from_vec(vec!["Alice", "Bob", "Carol"], Some("name")))?;
df.add_column("age".to_string(),
    Series::from_vec(vec![30, 25, 35], Some("age")))?;
df.add_column("salary".to_string(),
    Series::from_vec(vec![75000.0, 65000.0, 85000.0], Some("salary")))?;

// Perform operations
let filtered = df.filter("age > 25")?;
let mean_salary = df.column("salary")?.mean()?;
let grouped = df.groupby(vec!["department"])?.agg(HashMap::from([
    ("salary".to_string(), vec!["mean", "sum"]),
    ("age".to_string(), vec!["max"])
]))?;
```

## Core Features

### Data Structures

- **Series**: One-dimensional labeled array capable of holding any data type
- **DataFrame**: Two-dimensional, size-mutable, heterogeneous tabular data structure
- **MultiIndex**: Hierarchical indexing for advanced data organization
- **Categorical**: Memory-efficient representation for string data with limited cardinality

### Data Types

- Numeric: `i32`, `i64`, `f32`, `f64`, `u32`, `u64`
- String: UTF-8 encoded with automatic string pooling
- Boolean: Native boolean support
- DateTime: Timezone-aware datetime with nanosecond precision
- Categorical: Efficient storage for repeated string values
- Missing Values: First-class `NA` support across all types

### Operations

#### Data Manipulation
- Column addition, removal, and renaming
- Row and column selection with boolean indexing
- Sorting by single or multiple columns
- Duplicate detection and removal
- Data type conversion and casting

#### Aggregation & Grouping
- GroupBy operations with multiple aggregation functions
- Window functions (rolling, expanding, exponentially weighted)
- Pivot tables and cross-tabulation
- Custom aggregation functions

#### Joining & Merging
- Inner, left, right, and outer joins
- Merge on single or multiple keys
- Concat operations with axis control
- Append with automatic index alignment

#### Time Series
- DateTime indexing and slicing
- Resampling and frequency conversion
- Time zone handling and conversion
- Date range generation
- Business day calculations

### Performance Optimizations

#### SIMD Vectorization
- Automatic SIMD optimization for numerical operations
- Hand-tuned implementations for common operations
- Support for AVX2 and AVX-512 instruction sets

#### Parallel Processing
- Multi-threaded execution for large datasets
- Configurable thread pool sizing
- Parallel aggregations and transformations
- Load-balanced work distribution

#### Memory Efficiency
- Columnar storage format
- String interning with global string pool
- Copy-on-write semantics
- Memory-mapped file support
- Lazy evaluation for chain operations

### I/O Capabilities

#### File Formats
- **CSV**: Fast parallel CSV reader/writer
- **Parquet**: Apache Parquet with compression support
- **JSON**: Both records and columnar JSON formats
- **Excel**: XLSX/XLS read/write with multi-sheet support
- **SQL**: Direct database read/write
- **Arrow**: Zero-copy Arrow integration

#### Database Support
- PostgreSQL
- MySQL/MariaDB
- SQLite
- ODBC connectivity
- Connection pooling

#### Cloud Storage
- AWS S3
- Google Cloud Storage
- Azure Blob Storage
- HTTP/HTTPS endpoints

## Installation

Add to your `Cargo.toml`:

```toml
[dependencies]
pandrs = "0.1.0"
```

### Feature Flags

Enable additional functionality with feature flags:

```toml
[dependencies]
pandrs = { version = "0.1.0", features = ["stable"] }
```

Available features:
- **Core features:**
  - `stable`: Recommended stable feature set
  - `optimized`: Performance optimizations and SIMD
  - `backward_compat`: Backward compatibility support
- **Data formats:**
  - `parquet`: Parquet file support
  - `excel`: Excel file support
  - `sql`: Database connectivity
- **Advanced features:**
  - `distributed`: Distributed computing with DataFusion
  - `visualization`: Plotting capabilities
  - `streaming`: Real-time data processing
  - `serving`: Model serving and deployment
- **Experimental:**
  - `cuda`: GPU acceleration (requires CUDA toolkit)
  - `wasm`: WebAssembly compilation support
  - `jit`: Just-in-time compilation
- **Feature bundles:**
  - `all-safe`: All stable features (recommended)
  - `test-safe`: Features safe for testing

## Performance Benchmarks

Performance comparison with pandas (Python) and Polars (Rust):

| Operation | PandRS | Pandas | Polars | Speedup vs Pandas |
|-----------|--------|--------|--------|-------------------|
| CSV Read (1M rows) | 0.18s | 0.92s | 0.15s | 5.1x |
| GroupBy Sum | 0.09s | 0.31s | 0.08s | 3.4x |
| Join Operations | 0.21s | 0.87s | 0.19s | 4.1x |
| String Operations | 0.14s | 1.23s | 0.16s | 8.8x |
| Rolling Window | 0.11s | 0.43s | 0.12s | 3.9x |

*Benchmarks performed on AMD Ryzen 9 5950X, 64GB RAM, NVMe SSD*

## Documentation

- [API Documentation]https://docs.rs/pandrs
- [User Guide]https://github.com/cool-japan/pandrs/wiki
- [Examples]https://github.com/cool-japan/pandrs/tree/main/examples
- [Migration from Pandas]https://github.com/cool-japan/pandrs/wiki/Migration-Guide

## Examples

### Basic Data Analysis

```rust
use pandrs::prelude::*;

let df = DataFrame::read_csv("data.csv", CsvReadOptions::default())?;

// Basic statistics
let stats = df.describe()?;
println!("Data statistics:\n{}", stats);

// Filtering and aggregation
let result = df
    .filter("age >= 18 && income > 50000")?
    .groupby(vec!["city", "occupation"])?
    .agg(HashMap::from([
        ("income".to_string(), vec!["mean", "median", "std"]),
        ("age".to_string(), vec!["mean"])
    ]))?
    .sort_values(vec!["income_mean"], vec![false])?;
```

### Time Series Analysis

```rust
use pandrs::prelude::*;
use chrono::{Duration, Utc};

let mut df = DataFrame::read_csv("timeseries.csv", CsvReadOptions::default())?;
df.set_index("timestamp")?;

// Resample to daily frequency
let daily = df.resample("D")?.mean()?;

// Calculate rolling statistics
let rolling_stats = daily
    .rolling(RollingOptions {
        window: 7,
        min_periods: Some(1),
        center: false,
    })?
    .agg(HashMap::from([
        ("value".to_string(), vec!["mean", "std"]),
    ]))?;

// Exponentially weighted moving average
let ewm = daily.ewm(EwmOptions {
    span: Some(10.0),
    ..Default::default()
})?;
```

### Machine Learning Pipeline

```rust
use pandrs::prelude::*;

// Load and preprocess data
let df = DataFrame::read_parquet("features.parquet")?;

// Handle missing values
let df_filled = df.fillna(FillNaOptions::Forward)?;

// Encode categorical variables
let df_encoded = df_filled.get_dummies(vec!["category1", "category2"], None)?;

// Normalize numerical features
let features = vec!["feature1", "feature2", "feature3"];
let df_normalized = df_encoded.apply_columns(&features, |series| {
    let mean = series.mean()?;
    let std = series.std(1)?;
    series.sub_scalar(mean)?.div_scalar(std)
})?;

// Split features and target
let X = df_normalized.drop(vec!["target"])?;
let y = df_normalized.column("target")?;
```

## Contributing

We welcome contributions! Please see our [Contributing Guide](CONTRIBUTING.md) for details.

### Development Setup

```bash
# Clone the repository
git clone https://github.com/cool-japan/pandrs
cd pandrs

# Install development dependencies
cargo install cargo-nextest cargo-criterion

# Run tests
cargo nextest run

# Run benchmarks
cargo criterion

# Check code quality
cargo clippy -- -D warnings
cargo fmt -- --check
```

## License

Licensed under either of:

- Apache License, Version 2.0 ([LICENSE-APACHE]LICENSE-APACHE or <http://www.apache.org/licenses/LICENSE-2.0>)
- MIT license ([LICENSE-MIT]LICENSE-MIT or <http://opensource.org/licenses/MIT>)

at your option.

## Acknowledgments

PandRS is inspired by the excellent pandas library and incorporates ideas from:
- [Pandas]https://pandas.pydata.org/ - API design and functionality
- [Polars]https://www.pola.rs/ - Performance optimizations
- [Apache Arrow]https://arrow.apache.org/ - Columnar format
- [DataFusion]https://arrow.apache.org/datafusion/ - Query engine

## Support

- [Issue Tracker]https://github.com/cool-japan/pandrs/issues
- [Discussions]https://github.com/cool-japan/pandrs/discussions
- [Stack Overflow]https://stackoverflow.com/questions/tagged/pandrs

---

PandRS is a Cool Japan project, bringing high-performance data analysis to the Rust ecosystem.