Python library/tools for combining and parsing using Regular Expressions in a maintainable way
This library also allows you to:
- Maintain a database of Regular Expressions
- Combine them together using Patterns
- Search, Parse and Output data matched by combined Regex using Python functions.
This library basically just gives you a way to combine Regular Expressions together and hook them up to some callback functions in Python.
A Taste / Getting Started¶
(See the examples/ directory for a full code examples)
Say your fashionista friend must know what colors their friends like at certain times. Luckily for you two, your friend’s friends are blogging fanatics and you have downloaded thousands of text documents containing their every thought.
So you want to get (color and time) or
[('green', datetime.time(23, 0))] out of text like:
blah blah blah go to the store to buy green at 11pm! blah blah
If you need scan/search/parse/transform some unstructured input and get some semi-structured data out of it RE|PARSE might be able to help.
First structure some Regular Expressions (Here, in Yaml)¶
Color: Basic Color: Expression: (Red|Orange|Yellow|Green|Blue|Violet|Brown|Black) Matches: Orange | Green Non-Matches: White Groups: - Color Time: Basic Time: Expression: ([0-9]|[0-2]) \s? (am|pm) Matches: 8am | 3 pm Non-Matches: 8a | 8:00 am | 13pm Groups: - Hour - AMPM
Then structure some Patterns with those expressions (Yaml)¶
BasicColorTime: Order: 1 Pattern: | <Color> \s? at \s? <Time> # Angle brackets detonate expression groups # Multiple expressions in one group are combined together
Some callback functions (in Python)¶
from datetime import time def color_time(Color=None, Time=None): Color, Hour, Period = Color, int(Time), Time if Period == 'pm': Hour += 12 Time = time(hour=Hour) return Color, Time
Build your parser¶
from examples.colortime.functions import functions import reparse colortime_parser = reparse.parser( parser_type=reparse.basic_parser, expressions_yaml_path=path + "expressions.yaml", patterns_yaml_path=path + "patterns.yaml", functions=functions ) print(colortime_parser("~ ~ ~ go to the store ~ buy green at 11pm! ~ ~"))
pip install reparse
- If you don’t have them already,
RE|PARSE depends on REGEX, and PyYaml.
Download those and
python setup.py installin their directories. If you are on windows, you may have to find binary installers for these, since they contain modules that have to be compiled.
- Download the Zip off of Github (or clone the repo).
- Extract and do
python setup.py installin the reparse containing the setup.py file directory. You can also just have the reparse/reparse directory in the source tree of your project if you don’t want to install it.
- Test with
python -c "import reparse", no output means it is probably installed. If you get
ImportError: No module named reparsethen you might want to recheck your steps.
The code is located on Github. Send me suggestions, issues, and pull requests and I’ll gladly review them!
- 2.1 Change yaml.load to yaml.safe_load for security
- 2.0 Major Refactor, Python 3, Better Parser builders
- 1.1 Fix setup.py
- 1.0 Release
MIT Licensed! See LICENSE file for the full text.