python实现将英文单词表示的数字转换成阿拉伯数字的方法

import re
_known = {
  'zero': 0,'one': 1,'two': 2,'three': 3,'four': 4,'five': 5,'six': 6,'seven': 7,'eight': 8,'nine': 9,'ten': 10,'eleven': 11,'twelve': 12,'thirteen': 13,'fourteen': 14,'fifteen': 15,'sixteen': 16,'seventeen': 17,'eighteen': 18,'nineteen': 19,'twenty': 20,'thirty': 30,'forty': 40,'fifty': 50,'sixty': 60,'seventy': 70,'eighty': 80,'ninety': 90
  }
def spoken_word_to_number(n):
  """Assume n is a positive integer".
assert _positive_integer_number('nine hundred') == 900
assert spoken_word_to_number('one hundred') == 100
assert spoken_word_to_number('eleven') == 11
assert spoken_word_to_number('twenty two') == 22
assert spoken_word_to_number('thirty-two') == 32
assert spoken_word_to_number('forty two') == 42
assert spoken_word_to_number('two hundred thirty two') == 232
assert spoken_word_to_number('two thirty two') == 232
assert spoken_word_to_number('nineteen hundred eighty nine') == 1989
assert spoken_word_to_number('nineteen eighty nine') == 1989
assert spoken_word_to_number('one thousand nine hundred and eighty nine') == 1989
assert spoken_word_to_number('nine eighty') == 980
assert spoken_word_to_number('nine two') == 92 # wont be able to convert this one
assert spoken_word_to_number('nine thousand nine hundred') == 9900
assert spoken_word_to_number('one thousand nine hundred one') == 1901
"""
  n = n.lower().strip()
  if n in _known:
    return _known[n]
  else:
    inputWordArr = re.split('[ -]',n)
  assert len(inputWordArr) > 1 #all single words are known
  #Check the pathological case where hundred is at the end or thousand is at end
  if inputWordArr[-1] == 'hundred':
    inputWordArr.append('zero')
    inputWordArr.append('zero')
  if inputWordArr[-1] == 'thousand':
    inputWordArr.append('zero')
    inputWordArr.append('zero')
    inputWordArr.append('zero')
  if inputWordArr[0] == 'hundred':
    inputWordArr.insert(0,'one')
  if inputWordArr[0] == 'thousand':
    inputWordArr.insert(0,'one')
  inputWordArr = [word for word in inputWordArr if word not in ['and','minus','negative']]
  currentPosition = 'unit'
  prevPosition = None
  output = 0
  for word in reversed(inputWordArr):
    if currentPosition == 'unit':
      number = _known[word]
      output += number
      if number > 9:
        currentPosition = 'hundred'
      else:
        currentPosition = 'ten'
    elif currentPosition == 'ten':
      if word != 'hundred':
        number = _known[word]
        if number < 10:
          output += number*10
        else:
          output += number
      #else: nothing special
      currentPosition = 'hundred'
    elif currentPosition == 'hundred':
      if word not in [ 'hundred','thousand']:
        number = _known[word]
        output += number*100
        currentPosition = 'thousand'
      elif word == 'thousand':
        currentPosition = 'thousand'
      else:
        currentPosition = 'hundred'
    elif currentPosition == 'thousand':
      assert word != 'hundred'
      if word != 'thousand':
        number = _known[word]
        output += number*1000
    else:
      assert "Can't be here" == None
  return(output)