Converting Unicode Sentences To Snake Case In SQL and Python

to_snake_case.py

import re

import unidecode


def to_snake_case(text):
    """
    Convert unicode text to snake case

    >>> to_snake_case("My favourite dish was raclette.")
    'my_favourite_dish_was_raclette'

    >>> to_snake_case("My favourite dish now is Soupe à l'oignon.")
    'my_favourite_dish_now_is_soupe_a_l_oignon'
    """
    text = unidecode.unidecode(text.strip()).lower()
    text = re.sub(r'[^a-z0-9\\-]+', '_', text)
    return text.strip("_")

to_snake_case.sql

// Tested on Postgres 13
CREATE EXTENSION IF NOT EXISTS unaccent;

CREATE OR REPLACE FUNCTION public.to_snake_case(
    v TEXT
) RETURNS TEXT
    LANGUAGE plpgsql
    STRICT IMMUTABLE AS
$function$
BEGIN
    -- 1. trim trailing and leading whitespaces from text
    -- 2. remove accents (diacritic signs) from a given text
    -- 3. lowercase unaccented text
    -- 4. replace non-alphanumeric (excluding hyphen, underscore) with an underscore
    -- 5. trim leading and trailing hyphens
    RETURN trim(BOTH '_' FROM regexp_replace(lower(unaccent(trim(v))), '[^a-z0-9\\-]+', '_', 'gi'));
END;
$function$;