Minimal, super readable string pattern matching for python.
import simplematch
simplematch.match("He* {planet}!", "Hello World!")
>>> {"planet": "World"}
simplematch.match("It* {temp:float}°C *", "It's -10.2°C outside!")
>>> {"temp": -10.2}pip install simplematch
(Or just drop the simplematch.py file in your project.)
simplematch has only two syntax elements:
- wildcard
* - capture group
{name}
Capture groups can be named ({name}), unnamed ({}) and typed ({name:float}).
The following types are available:
intfloatemailurlipv4ipv6bitcoin-
ssn(social security number) -
ccard(matches Visa, MasterCard, American Express, Diners Club, Discover, JCB)
For now, only named capture groups can be typed.
Then use one of these functions:
import simplematch
simplematch.match(pattern, string) # -> returns a `dict` on match, `None` otherwise.
simplematch.test(pattern, string) # -> returns `True` on match, `False` otherwise.Or use a Matcher object:
import simplematch as sm
matcher = sm.Matcher(pattern)
matcher.match(string) # -> returns a dict or None
matcher.test(string) # -> returns True / False
matcher.regex # -> shows the generated regeximport simplematch as sm
# extracting data
sm.match(
pattern="Invoice_*_{year}_{month}_{day}.pdf",
string="Invoice_RE2321_2021_01_15.pdf")
>>> {"year": "2021", "month": "01", "day": "15"}
# test match only
sm.test("ABC-{value:int}", "ABC-13")
>>> Trueimport simplematch as sm
matcher = sm.Matcher("{year:int}-{month:int}: {value:float}")
# extracting data
matcher.match("2021-01: -12.786")
>>> {"year": 2021, "month": 1, "value": -12.786}
# month is no integer -> no match and return `None`.
matcher.match("2021-AB: Hello")
>>> None
# no extraction, only test for match
matcher.test("1234-01: 123.123")
>>> True
# show generated regular expression
matcher.regex
>>> '^(?P<year>[+-]?[0-9]+)\\-(?P<month>[+-]?[0-9]+):\\ (?P<value>[+-]?(?:[0-9]*[.])?[0-9]+)$'
# show registered converters
matcher.converters
>>> {'year': <class 'int'>, 'month': <class 'int'>, 'value': <class 'float'>}You can register your own types to be available for the {name:type} matching syntax
with the register_type function.
simplematch.register_type(name, regex, converter=str)
-
nameis the name to use in the matching syntax -
regexis a regular expression to match your type -
converteris a callable to convert a match (strby default)
Register a smiley type to detect smileys (:), :(, :/) and getting their moods:
import simplematch as sm
def mood_convert(smiley):
moods = {
":)": "good",
":(": "bad",
":/": "sceptic",
}
return moods.get(smiley, "unknown")
sm.register_type("smiley", r":[\)\(\/]", mood_convert)
sm.match("I'm feeling {mood:smiley} *", "I'm feeling :) today!")
>>> {"mood": "good"}You can also install simplematch for use as a CLI command e.g. using pipx.
pipx install simplematchusage: simplematch [-h] [--regex] pattern [strings ...]
positional arguments:
pattern A matching pattern
strings The string to match
options:
-h, --help show this help message and exit
--regex Show the generated regular expressionExtract a date from a specific file name:
simplematch "Invoice_*_{year}_{month}_{day}.pdf" "Invoice_RE2321_2021_01_15.pdf"
>>> {"year": "2021", "month": "01", "day": "15"}simplematch aims to fill a gap between parsing with str.split() and regular
expressions. It should be as simple as possible, fast and stable.
The simplematch syntax is transpiled to regular expressions under the hood, so
matching performance should be just as good.
I hope you get some good use out of this!
Contributions are welcome! Just submit a PR and maybe get in touch with me via email before big changes.
![dependabot[bot]](https://avatars.githubusercontent.com/u/49699333?size=120)
