arabic to chinese number conversion 数字中文读法生成器

zhnum.py

import bisect
import re
import unittest


zhdigits = '零一二三四五六七八九'
zhplaces = {
  0: ''  ,
  1: '十',
  2: '百',
  3: '千',
  4: '万',
  8: '亿',
}
zhplace_keys = sorted(zhplaces.keys())


def numdigits(n):
  return len(str(abs(n)))

# # An alternative to using regex for 二 vs 两.
# def _place_with_alttwo(amount, unit):
#   if amount == 2 and unit in set('亿万千'):
#     return f'两{unit}'
#   return f'{_zhnum(amount)}{unit}'

def _zhnum(n):
  if n < 10:
    return zhdigits[n]
  # Largest place length (number of trailing digits) with a name
  # that fits `n`.
  # Examples:
  #     n       | LPL | name
  #     ---     | --- | ---
  #     100     | 2   | 百
  #     10_0000 | 4   | 万
  named_place_len = zhplace_keys[bisect.bisect_right(zhplace_keys,
                                                     numdigits(n)-1) - 1]
  # Break `n` on the `named_place_len`. The final answer (without handling
  # grammar exceptions like '十' instead of '一十') will generally be
  #     zhnum(left_part) + unit name at `named_place_len` + zhnum(right_part)
  # additionally, if the `right_part` has leading zeros, a complimenting '零'
  # should lead it.
  # Examples:
  #
  #                208|0300
  #             /           \
  #           /              \
  #        2|08      万  零 3|00
  #      /      \          /   \
  #    二 百 零 八       三 百 empty
  left_part, right_part = n // 10**named_place_len, n % 10**named_place_len
  return (_zhnum(left_part) +
          zhplaces[named_place_len] +
          ((zhdigits[0] if numdigits(right_part) != named_place_len else '') +
           _zhnum(right_part)
           if right_part else ''))

def zhnum(n):
  answer = ('负' if n < 0 else '') + _zhnum(abs(n))
  answer = re.sub(r'^一十', '十', answer)
  answer = re.sub(r'(?<![零十])二(?=[千万亿])', r'两', answer)
  return answer


class TestZhnum(unittest.TestCase):
  def test(self):
    self.assertEqual(zhnum(-1),                    '负一')
    self.assertEqual(zhnum(0),                     '零')
    self.assertEqual(zhnum(-0),                    '零')
    self.assertEqual(zhnum(6),                     '六')
    self.assertEqual(zhnum(10),                    '十')
    self.assertEqual(zhnum(14),                    '十四')
    self.assertEqual(zhnum(28),                    '二十八')
    self.assertEqual(zhnum(59),                    '五十九')
    self.assertEqual(zhnum(100),                   '一百')
    self.assertEqual(zhnum(101),                   '一百零一')
    self.assertEqual(zhnum(110),                   '一百一十')
    self.assertEqual(zhnum(132),                   '一百三十二')
    self.assertEqual(zhnum(1000),                  '一千')
    self.assertEqual(zhnum(2001),                  '两千零一')
    self.assertEqual(zhnum(3010),                  '三千零一十')
    self.assertEqual(zhnum(4012),                  '四千零一十二')
    self.assertEqual(zhnum(5230),                  '五千二百三十')
    self.assertEqual(zhnum(6234),                  '六千二百三十四')
    self.assertEqual(zhnum(9999),                  '九千九百九十九')
    self.assertEqual(zhnum(1_0000),                '一万')
    self.assertEqual(zhnum(20_0000),               '二十万')
    self.assertEqual(zhnum(123_4567),              '一百二十三万四千五百六十七')
    self.assertEqual(zhnum(500_1024),              '五百万一千零二十四')
    self.assertEqual(zhnum(360_5000),              '三百六十万五千')
    self.assertEqual(zhnum(3_0000_0000),           '三亿')
    self.assertEqual(zhnum(2_7600_2010),           '两亿七千六百万两千零一十')
    self.assertEqual(zhnum(2_0000_0000_0000_0000), '两亿亿')
    self.assertEqual(zhnum(2_2002_2222),           '两亿两千零二万两千二百二十二')
    self.assertEqual(zhnum(22_2222_2222),          '二十二亿两千二百二十二万两千二百二十二')

if __name__ == '__main__':
  unittest.main()