numbers.py

# *****************************************************************************
# Copyright (c) 2017 Keith Ito
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
# *****************************************************************************
"""
Modified from https://github.com/keithito/tacotron
"""

import inflect
import re


_inflect = inflect.engine()
_comma_number_re = re.compile(r'([0-9][0-9\,]+[0-9])')
_decimal_number_re = re.compile(r'([0-9]+\.[0-9]+)')
_pounds_re = re.compile(r'£([0-9\,]*[0-9]+)')
_dollars_re = re.compile(r'\$([0-9\.\,]*[0-9]+)')
_ordinal_re = re.compile(r'[0-9]+(st|nd|rd|th)')
_number_re = re.compile(r'[0-9]+')


def _remove_commas(m: re.Match) -> str:
    return m.group(1).replace(',', '')


def _expand_decimal_point(m: re.Match) -> str:
    return m.group(1).replace('.', ' point ')


def _expand_dollars(m: re.Match) -> str:
    match = m.group(1)
    parts = match.split('.')
    if len(parts) > 2:
        return match + ' dollars'  # Unexpected format
    dollars = int(parts[0]) if parts[0] else 0
    cents = int(parts[1]) if len(parts) > 1 and parts[1] else 0
    if dollars and cents:
        dollar_unit = 'dollar' if dollars == 1 else 'dollars'
        cent_unit = 'cent' if cents == 1 else 'cents'
        return '%s %s, %s %s' % (dollars, dollar_unit, cents, cent_unit)
    elif dollars:
        dollar_unit = 'dollar' if dollars == 1 else 'dollars'
        return '%s %s' % (dollars, dollar_unit)
    elif cents:
        cent_unit = 'cent' if cents == 1 else 'cents'
        return '%s %s' % (cents, cent_unit)
    else:
        return 'zero dollars'


def _expand_ordinal(m: re.Match) -> str:
    return _inflect.number_to_words(m.group(0))


def _expand_number(m: re.Match) -> str:
    num = int(m.group(0))
    if num > 1000 and num < 3000:
        if num == 2000:
            return 'two thousand'
        elif num > 2000 and num < 2010:
            return 'two thousand ' + _inflect.number_to_words(num % 100)
        elif num % 100 == 0:
            return _inflect.number_to_words(num // 100) + ' hundred'
        else:
            return _inflect.number_to_words(num, andword='', zero='oh', group=2).replace(', ', ' ')
    else:
        return _inflect.number_to_words(num, andword='')


def normalize_numbers(text: str) -> str:
    text = re.sub(_comma_number_re, _remove_commas, text)
    text = re.sub(_pounds_re, r'\1 pounds', text)
    text = re.sub(_dollars_re, _expand_dollars, text)
    text = re.sub(_decimal_number_re, _expand_decimal_point, text)
    text = re.sub(_ordinal_re, _expand_ordinal, text)
    text = re.sub(_number_re, _expand_number, text)
    return text