EXREX

Irregular methods for regular expressions.

Exrex is a command line tool and python module that generates all - or random - matching strings to a given regular expression and more. It's pure python, without external dependencies.

There are regular expressions with infinite matching strings (eg.: [a-z]+), in these cases exrex limits the maximum length of the infinite parts.

Exrex uses generators, so the memory usage does not depend on the number of matching strings.

Features

• Generating all matching strings
• Generating a random matching string
• Counting the number of matching strings
• Simplification of regular expressions

Installation

To install exrex, simply:

$ pip install exrex

or

$ easy_install exrex

Usage

as python module

>>> import exrex

>>> exrex.getone('(ex)r\\1')
'exrex'

>>> list(exrex.generate('((hai){2}|world!)'))
['haihai', 'world!']

>>> exrex.getone('\d{4}-\d{4}-\d{4}-[0-9]{4}')
'3096-7886-2834-5671'

>>> exrex.getone('(1[0-2]|0[1-9])(:[0-5]\d){2} (A|P)M')
'09:31:40 AM'

>>> exrex.count('[01]{0,9}')
1023

>>> print '\n'.join(exrex.generate('This is (a (code|cake|test)|an (apple|elf|output))\.'))
This is a code.
This is a cake.
This is a test.
This is an apple.
This is an elf.
This is an output.

>>> print exrex.simplify('(ab|ac|ad)')
(a[bcd])

Command line usage

> exrex --help
usage: exrex.py [-h] [-o FILE] [-l] [-d DELIMITER] [-v] REGEX

exrex - regular expression string generator

positional arguments:
  REGEX                 REGEX string

optional arguments:
  -h, --help            show this help message and exit
  -o FILE, --output FILE
                        Output file - default is STDOUT
  -l N, --limit N       Max limit for range size - default is 20
  -c, --count           Count matching strings
  -m N, --max-number N  Max number of strings - default is -1
  -r, --random          Returns a random string that matches to the regex
  -s, --simplify        Simplifies a regular expression
  -d DELIMITER, --delimiter DELIMITER
                        Delimiter - default is \n
  -v, --verbose         Verbose mode

Examples:

$ exrex '[asdfg]'
a
s
d
f
g

$ exrex -r '(0[1-9]|1[012])-\d{2}'
09-85

$ exrex '[01]{10}' -c
1024

Bugs

Bugs or suggestions? Visit the issue tracker.

Documentation

http://exrex.readthedocs.org/en/latest/

TODO

• Command line switches to change default character sets/ranges/range limits (eg. for '.','\s'..) (40%)
• Extend categories (re.sre_parse.CATEGORIES) (30%)
• Improve setup.py
• More verbose code
• Documentation
• Optimizations
• Generation of n different random matching string
• Memory usage reduction (100%?) - generators
• Count the number of matching strings - (100%?)
• Unicode support (100%)
• Handle grouprefs (100%)
• Python3 compatibility (100%) ( >= python3.3)

License

exrex is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

exrex is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License
along with exrex. If not, see < http://www.gnu.org/licenses/ >.

(C) 2012- by Adam Tauber, <asciimoo@gmail.com>

Fun/arts

• Boat: exrex '( {20}(\| *\\|-{22}|\|)|\.={50}| ( ){0,5}\\\.| {12}~{39})'
• Eyes: exrex '(o|O|0)(_)(o|O|0)'

Similar projects

Tools that generate a list of all possible strings that match a given pattern:

• regldg (features a live demo on the website)
• regex-genex (supports using multiple regex patterns simultaneously)

Tools that generate random strings, one by one, that match a given pattern:

• randexp.js (features several live demos on the website)
• rstr.xeger (a method of the rstr Python module)

Profiling

• python -m cProfile exrex.py '[a-zA-Z][a-zA-Z][a-zA-Z][a-zA-Z]' -o /dev/null
• python -m cProfile exrex.py '[0-9]{6}' -o /dev/null