lookup.py

# Standard library imports
import re

# Third-party imports
import editdistance
import unidecode

def convert_to_expression(string):
	patterns = ['\w', '\s']
	expression = ''
	previous = None

	for letter in string:
		for pattern in patterns:
			if re.match(pattern, letter):
				if not previous == pattern:
					previous = pattern
					expression += '{}+'.format(pattern)
				break
		else:
			previous = letter
			expression += letter

	return expression

def count_fuzzy_matches(needle, haystack, maximum_distance=2, minimum_length=6):
	# We normalize the text to prevent skewed edit distance
	needle = unidecode.unidecode(needle).lower()
	haystack = haystack.lower()

	# We search without fuzz if the string is too short
	if len(needle) < minimum_length:
		return haystack.count(needle)

	expression = convert_to_expression(needle)
	matches = 0

	for match in re.finditer(expression, haystack):
		if editdistance.eval(match.group(0), needle) <= maximum_distance:
			matches += 1

	return matches