Range-Ex

This tool builds a regular expression for a numerical range.

Installation

pip install range-ex

Usage

Use range_regex for integer ranges and float_range_regex for decimal ranges.

Integer ranges (range_regex)

range_regex matches only integers (including negatives). The range is inclusive on both ends.

from range_ex import range_regex

regex1 = range_regex(5, 89)
# (?:[5-9]|[2-7]\d|1\d|8\d)

regex2 = range_regex(-65, 12)
# (?:\-[1-9]|\-[2-5]\d|\-1\d|\-6[0-5]|\d|1[0-2])

If you pass only one bound, the other is unbounded:

regex3 = range_regex(minimum=5)
# (?:[5-9]|[1-9]\d(?:\d)*)

regex4 = range_regex(maximum=89)
# (?:\-[1-9](?:\d)*|\d|[2-7]\d|1\d|8\d)

regex5 = range_regex()
# (?:\-[1-9](?:\d)*|[1-9](?:\d)*|0)

Decimal ranges (float_range_regex)

float_range_regex accepts int, float, Decimal, and decimal-parseable str bounds.

from range_ex import float_range_regex

regex6 = float_range_regex(0.5, 1.5, strict=True)
# (?:(?:0)?\.[5-9](?:\d)*|1\.[0-5](?:\d)*)

regex7 = float_range_regex(0.5, 1.5, strict=False)
# (?:1|(?:0)?\.[5-9](?:\d)*|1\.[0-5](?:\d)*)

regex8 = float_range_regex(maximum="1.5", strict=True)
# (?:\-[1-9](?:\d)*\.\d(?:\d)*|(?:0)?\.\d(?:\d)*|1\.[0-5](?:\d)*)

regex9 = float_range_regex(strict=True)
# (?:(?:\-)?(?:0|[1-9](?:\d)*)\.\d(?:\d)*|(?:\-)?(?:0|[1-9](?:\d)*)\.|(?:\-)?\.\d(?:\d)*)

Rendering options

Both APIs support capturing=True to emit capturing groups ((...)) instead of non-capturing groups ((?:...)):

range_regex(-65, 12, capturing=True)
# (\-[1-9]|\-[2-5]\d|\-1\d|\-6[0-5]|\d|1[0-2])

Note: Generated regexes can still match inside larger strings (for example, inside abc25def). Use anchors like ^...$ if you need whole-string matches.

Contributing

Contributions are very welcome. Please open an issue or a pull request if you have any suggestions or improvements.

To test your changes, run the following command:

pytest -n 5

Acknowledgements

This project is based on regex_engine. Feel free to check it out.