Skip to main content
Pre-release

This release is a pre-release and may not be stable for production use.

PyParsing – A Python Parsing Module

Version Build Status Coverage License Python versions pyparsing

Introduction

The pyparsing module is an alternative approach to creating and executing simple grammars, vs. the traditional lex/yacc approach, or the use of regular expressions. The pyparsing module provides a library of classes that client code uses to construct the grammar directly in Python code.

[Since first writing this description of pyparsing in late 2003, this technique for developing parsers has become more widespread, under the name Parsing Expression Grammars - PEGs. See more information on PEGs here .]

Here is a program to parse "Hello, World!" (or any greeting of the form "salutation, addressee!"):

from pyparsing import Word, alphas
greet = Word(alphas) + "," + Word(alphas) + "!"
hello = "Hello, World!"
print(hello, "->", greet.parse_string(hello))

The program outputs the following:

Hello, World! -> ['Hello', ',', 'World', '!']

The Python representation of the grammar is quite readable, owing to the self-explanatory class names, and the use of ‘+’, ‘|’ and ‘^’ operator definitions.

The parsed results returned from parse_string() is a collection of type ParseResults, which can be accessed as a nested list, a dictionary, or an object with named attributes.

The pyparsing module handles some of the problems that are typically vexing when writing text parsers:

  • extra or missing whitespace (the above program will also handle "Hello,World!", "Hello , World !", etc.)

  • quoted strings

  • embedded comments

The examples directory includes a simple SQL parser, simple CORBA IDL parser, a config file parser, a chemical formula parser, and a four- function algebraic notation parser, among many others.

Documentation

There are many examples in the online docstrings of the classes and methods in pyparsing. You can find them compiled into online docs. Additional documentation resources and project info are listed in the online GitHub wiki. An entire directory of examples can be found here.

AI Instructions

There are also instructions for AI agents to use when helping you to create your parser. They can be pulled from the GitHub project repository, at pyparsing/ai/best_practices.md. You can also tell the AI to access them programmatically after installing pyparsing, either from the CLI with python -m pyparsing.ai.show_best_practices or within python with import pyparsing; pyparsing.show_best_practices().

License

MIT License. See header of the pyparsing __init__.py file.

History

See CHANGES file.

Performance benchmarks

For usage instructions and details on the performance benchmark suite, see tests/README.md in this repository.

Metadata

Release files for pyparsing 3.3.0b1

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Source distribution (sdist)

Source distribution for pyparsing 3.3.0b1
File Size Uploaded Provenance
pyparsing-3.3.0b1.tar.gz 1.2 MB Without provenance Details

Built distribution (wheel)

Table of built distributions (wheels) for pyparsing 3.3.0b1
File Interpreter ABI Platform
pyparsing-3.3.0b1-py3-none-any.whl Python 3 none any Details

Total release size: 1.3 MB

Release files / pyparsing-3.3.0b1.tar.gz

Download URL pyparsing-3.3.0b1.tar.gz
Size 1.2 MB
Tags Source
SHA-256 checksum
How to use checksums
c8c97e69eb6dc535eda2c43be866a6220e8d77357027202b66cae234c37709fa
BLAKE2b-256 checksum
How to use checksums
d05ceab45b9aed0859326d0d4223baa7389c3e353e8488ce5c712297f8849885
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/6.2.0 CPython/3.13.7

Release files / pyparsing-3.3.0b1-py3-none-any.whl

Download URL pyparsing-3.3.0b1-py3-none-any.whl
Size 122.3 kB
Tags Python 3
SHA-256 checksum
How to use checksums
61e401b24d26cd16935179f91c908ade7eff41c9ca6ec28314b42c0f371b9772
BLAKE2b-256 checksum
How to use checksums
2169be464cd78cdaa7b8974c95387ea411deba2fb441e2f9c806a94e7e6488ab
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/6.2.0 CPython/3.13.7

Security for pyparsing 3.3.0b1

Provenance

Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.

No provenance found

None of the files in this release were uploaded with provenance metadata.

A note on package security

PyPI is a repository for distributing packages, not a service for auditing them. While third-party security researchers and our staff do their best to detect and remove malicious packages, PyPI cannot guarantee the quality, security or suitability of any given package.

To learn more about protecting yourself from malicious actors, visit our package security documentation.

Release history Release notifications | RSS feed

This release

1.3.3

1.2

1.1.2

Anthropic, PBC Visionary sponsor Bloomberg Visionary sponsor Hudson River Trading Visionary sponsor Meta Visionary sponsor NVIDIA Visionary sponsor Microsoft Sustainability sponsor Depot Continuous Integration AWS Cloud computing and Security Sponsor Datadog Monitoring Fastly CDN Google Download Analytics Sentry Error logging StatusPage Status page