pytrovich is a Python 3.9+ port of petrovich library which inflects Russian names to a given grammatical case. It supports first names, last names and middle names inflections. Since version 0.0.2, gender detection is also available.

It is STRONGLY RECOMMENDED to use pytrovich VERSION >=0.1.0

3–5× faster lookups via a suffix trie, 800× faster repeated construction via parsed-rules caching, deterministic gender output, correct handling of all-caps / Ё / indeclinable names that previously failed silently, and refreshed rules data covering 24 upstream fixes from 2020–2024. Upgrade because the old version returned wrong answers on a non-trivial slice of real Russian names (try make(LASTNAME, MALE, GEN, "ИВАНОВ") or make(FIRSTNAME, MALE, GEN, "Пётр") on both --- the new one is correct, the old one isn't), flapped between gender predictions across runs, and crashed on unknown names; the new one is faster, deterministic, properly typed (py.typed ships), and benchmarked at >99% accuracy across 270k gold-standard inflections.

petrovich-java was the main inspiration.

The alternative (earlier) port: Petrovich (@alexeyev was not aware of it at the time of porting petrovich to Python). The only meaningful difference we have found is that it does not support gender detection.

Installation

Should be as simple as that

pip install pytrovich

Usage

Inflection

from pytrovich.enums import NamePart, Gender, Case
from pytrovich.maker import PetrovichDeclinationMaker

maker = PetrovichDeclinationMaker()
print(maker.make(NamePart.FIRSTNAME, Gender.MALE, Case.GENITIVE, "Иван"))  # Ивана
print(maker.make(NamePart.LASTNAME, Gender.MALE, Case.INSTRUMENTAL, "Иванов"))  # Ивановым
print(maker.make(NamePart.MIDDLENAME, Gender.FEMALE, Case.DATIVE, "Ивановна"))  # Ивановне

Inflection follows the canonical petrovich-ruby reference semantics, verified row-for-row against the petrovich-eval corpus:

• hyphenated double names decline per component (Салтыков-Щедрин → dative Салтыкову-Щедрину);
• exception rules match whole words only (the surname Ельцин keeps the regular -ин declension instead of the Цин exception);
• the optional known_gender flag (default True) marks the supplied gender as an explicit fact. Pass known_gender=False when the gender came out of PetrovichGenderDetector to get the Ruby reference's looser detected-gender rule filter:

gender = detector.detect(lastname="Цой")  # Gender.MALE
maker.make(NamePart.LASTNAME, gender, Case.DATIVE, "Цой", known_gender=False)  # Цою

Gender detection

from pytrovich.detector import PetrovichGenderDetector

detector = PetrovichGenderDetector()
print(detector.detect(firstname="Иван"))  # Gender.MALE
print(detector.detect(firstname="Иван", middlename="Семёнович"))  # Gender.MALE
print(detector.detect(firstname="Арзу", middlename="Лутфияр кызы"))  # Gender.FEMALE

Custom rule file

You can replace default rules file with some custom one. Only JSON format is supported.

maker = PetrovichDeclinationMaker("/path/to/custom/rules.file.json")

E.g. if pytrovich fails on PetrovichDeclinationMaker creation, one may consider downloading rules.json directly from petrovich-rules repo as a fix (please create an issue if that actually happens).

How to cite

Not neccessary, but greatly appreciated, if you use this work.

@misc{Pytrovich,
  title     = {{petrovich/pytrovich: Python3 port of Petrovich, an inflector for Russian anthroponyms}},
  year      = {2020},
  url       = {https://github.com/petrovich/pytrovich},
  language  = {english},
}

More info

For more information on the project please refer to other petrovich repos.

License

This project is available under MIT license.