Welcome To Datagrunt

Datagrunt is a Python library designed to simplify the way you work with CSV files. It provides a streamlined approach to reading, processing, and transforming your data into various formats, making data manipulation efficient and intuitive.

Why Datagrunt?

Born out of real-world frustration, Datagrunt eliminates the need for repetitive coding when handling CSV files. Whether you're a data analyst, data engineer, or data scientist, Datagrunt empowers you to focus on insights, not tedious data wrangling.

What Datagrunt Is Not

Datagrunt is not an extension of or a replacement for DuckDB, Polars, or PyArrow, nor is it a comprehensive data processing solution. Instead, it's designed to simplify the way you work with CSV files and to help solve the pain point of inferring delimiters when a file structure is unknown. Datagrunt provides an easy way to convert CSV files to dataframes and export them to various formats. One of Datagrunt's value propositions is its relative simplicity and ease of use.

Key Features

• Intelligent Delimiter Inference: Datagrunt automatically detects and applies the correct delimiter for your CSV files.
• Path Object Support: Full support for both string paths and pathlib.Path objects for modern, cross-platform file handling.
• Multiple Processing Engines: Choose from three powerful engines - DuckDB, Polars, and PyArrow - to handle your data processing needs.
• Flexible Data Transformation: Easily convert your processed CSV data into various formats including CSV, Excel, JSON, JSONL, and Parquet.
• AI-Powered Schema Analysis: Use Google's Gemini models to automatically generate detailed schema reports for your CSV files, including data types, column classifications, and data quality checks.
• Pythonic API: Enjoy a clean and intuitive API that integrates seamlessly into your existing Python workflows.

Powertools Under The Hood

Tool	Description
DuckDB	Fast in-process analytical database with excellent SQL support
Polars	Multi-threaded DataFrame library written in Rust, optimized for performance
PyArrow	Python bindings for Apache Arrow with efficient columnar data processing
Google Gemini	A powerful family of generative AI models for schema analysis

Installation

We recommend using UV. However, you may get started with Datagrunt in seconds using UV or pip.

Get started with UV:

uv pip install datagrunt

Get started with pip:

pip install datagrunt

Quick Start

Reading CSV Files with Multiple Engine Options

from datagrunt import CSVReader
from pathlib import Path

# Load your CSV file with different engines
# Accepts both string paths and Path objects
csv_file = 'electric_vehicle_population_data.csv'
csv_path = Path('electric_vehicle_population_data.csv')

# Choose your engine: 'polars' (default), 'duckdb', or 'pyarrow'
reader_polars = CSVReader(csv_file, engine='polars')    # String path - fast DataFrame ops
reader_duckdb = CSVReader(csv_path, engine='duckdb')    # Path object - best for SQL queries
reader_pyarrow = CSVReader(csv_file, engine='pyarrow')  # Arrow ecosystem integration

# Get a sample of the data
reader_duckdb.get_sample()

DuckDB Integration for Performant SQL Queries

from datagrunt import CSVReader

# Set up DuckDB engine for SQL capabilities
dg = CSVReader('electric_vehicle_population_data.csv', engine='duckdb')

# Construct your SQL query using the auto-generated table name
query = f"""
WITH core AS (
    SELECT
        City AS city,
        "VIN (1-10)" AS vin
    FROM {dg.db_table}
)
SELECT
    city,
    COUNT(vin) AS vehicle_count
FROM core
GROUP BY 1
ORDER BY 2 DESC
"""

# Execute the query and get results as a Polars DataFrame
df = dg.query_data(query).pl()
print(df)

Exporting Data to Multiple Formats

from datagrunt import CSVWriter
from pathlib import Path

# Create writer with your preferred engine (accepts both strings and Path objects)
input_file = Path('input.csv')
writer = CSVWriter(input_file, engine='duckdb')  # Default for exports

# Export to various formats
writer.write_csv('output.csv')          # Clean CSV export
writer.write_excel('output.xlsx')       # Excel workbook
writer.write_json('output.json')        # JSON format
writer.write_parquet('output.parquet')  # Parquet for analytics

# Use PyArrow engine for optimized Parquet exports
writer_arrow = CSVWriter('input.csv', engine='pyarrow')  # String path also works
writer_arrow.write_parquet('optimized.parquet')  # Native Arrow Parquet

AI-Powered Schema Analysis

from datagrunt import CSVSchemaReportAIGenerated
from pathlib import Path
import os

# Generate detailed schema reports with AI (accepts both strings and Path objects)
api_key = os.environ.get("GEMINI_API_KEY")
data_file = Path('your_data.csv')

schema_analyzer = CSVSchemaReportAIGenerated(
    filepath=data_file,  # Path object works seamlessly
    engine='google',
    api_key=api_key
)

# Get comprehensive schema analysis
report = schema_analyzer.generate_csv_schema_report(
    model='gemini-2.5-flash',
    return_json=True
)

print(report)  # Detailed JSON schema with data types, classifications, and more

Engine Comparison

Feature	Polars	DuckDB	PyArrow
Best for	DataFrame operations	SQL queries & analytics	Arrow ecosystem integration
Performance	Fast in-memory processing	Excellent for large datasets	Optimized columnar operations
Default for	CSVReader	CSVWriter	-
Export Quality	Good	Excellent (especially JSON)	Native Parquet support

Primary Classes

• CSVReader: Read and process CSV files with intelligent delimiter detection
• CSVWriter: Export CSV data to multiple formats (CSV, Excel, JSON, Parquet)
• CSVSchemaReportAIGenerated: Generate AI-powered schema analysis reports

Full Documentation

For complete documentation, detailed examples, and advanced usage patterns, see: 📖 Complete Documentation

License

This project is licensed under the MIT License

Acknowledgements

A HUGE thank you to the open source community and the creators of DuckDB, Polars, and PyArrow for their fantastic libraries that power Datagrunt.

Source Repository

https://github.com/pmgraham/datagrunt