mathparse

A secure, multilingual mathematical expression evaluator for Python

mathparse is a Python library that safely parses and evaluates mathematical expressions from strings, supporting both numeric operators and natural language words across 13+ languages. Unlike Python's dangerous eval() function, mathparse provides a secure, zero-dependency solution for evaluating user-provided mathematical expressions.

Why mathparse?

✅ Security First - Never uses eval(), protecting against arbitrary code execution
✅ Multilingual Support - Parse math in English, Spanish, French, German, Chinese, and 8+ more languages
✅ Zero Dependencies - Pure Python implementation with no external requirements
✅ Natural Language - Understands "fifty times twenty plus ten" alongside standard notation
✅ Production Ready - Used in chatbots, calculators, voice assistants, and educational applications
✅ Well Tested - Comprehensive test suite ensuring reliability

Quick Examples

from mathparse import mathparse

# Standard numeric expressions
mathparse.parse('50 * (85 / 100)')
>>> 42.5

# Natural language in English
mathparse.parse('one hundred times fifty four', language='ENG')
>>> 5400

# Mixed notation
mathparse.parse('(seven * nine) + 8 - (45 plus two)', language='ENG')
>>> 24

# Other languages (French, Spanish, German, Chinese, etc.)
mathparse.parse('cinq plus trois', language='FRE')
>>> 8

mathparse.parse('cinco más tres', language='ESP')
>>> 8

Use Cases

• 🤖 Chatbots & Voice Assistants - Parse natural language math queries
• 🧮 Calculator Applications - Build safe calculators that accept text input
• 📚 Educational Software - Evaluate student-provided math expressions
• 🌐 Multilingual Apps - Support math parsing in users' native languages
• 🔐 Secure Code Evaluation - Replace dangerous eval() calls with safe parsing
• 📊 Data Processing - Extract and calculate values from natural language text

Security: Why Not eval()?

Python's eval() function executes arbitrary code, creating severe security vulnerabilities:

# DANGEROUS - Never do this with user input!
eval("__import__('os').system('rm -rf /')")  # Deletes files
eval("__import__('requests').get('evil.com')")  # Network access

mathparse is the safe alternative:

mathparse uses postfix (Reverse Polish) notation internally, ensuring only valid mathematical operations are performed. See our security documentation for technical details.

Performance

• Fast: Simple numeric expressions parse in microseconds
• Efficient: Minimal memory footprint, suitable for high-volume applications
• Scalable: Linear time complexity for expression evaluation

Language Support

The language parameter must be set in order to evaluate an equation that uses word operators. The language code should be a valid ISO 639-2 language code.

Installation

pip install mathparse

Documentation

See the full documentation at https://mathparse.chatterbot.us

Changelog

See release notes for changes.