Python script to convert from numbers to words for printing cheques

Question

I think I can avoid reinventing the wheel here.

I need a Python script to convert from numbers to words for printing cheques.

E.g. 1,10,543 should provide output as One lac ten thousand five hundred and forty three.

Answer 1

Have written a custom converter with the foll features:

• Number to Word converter that can be used for numbers from 0 to 999999999 catering to Indian subcontinent i.e. lacs and crore (The range is big enough to accomodate lot of use cases)
• Includes paisa support upto 2 decimal places (rounded)
• Inspired by the post at http://www.blog.pythonlibrary.org/2010/10/21/python-converting-numbers-to-words/

• Profiling information: This script has lesser performace in terms of execution time of 0.458 seconds against 0.237 seconds of the above script for exactly 10000 runs.

  class Number2Words(object):
  
          def __init__(self):
              '''Initialise the class with useful data'''
  
              self.wordsDict = {1: 'one', 2: 'two', 3: 'three', 4: 'four', 5: 'five', 6: 'six', 7: 'seven',
                                8: 'eight', 9: 'nine', 10: 'ten', 11: 'eleven', 12: 'twelve', 13: 'thirteen',
                                14: 'fourteen', 15: 'fifteen', 16: 'sixteen', 17: 'seventeen',
                                18: 'eighteen', 19: 'nineteen', 20: 'twenty', 30: 'thirty', 40: 'forty',
                                50: 'fifty', 60: 'sixty', 70: 'seventy', 80: 'eighty', 90: 'ninty' }
  
              self.powerNameList = ['thousand', 'lac', 'crore']
  
  
          def convertNumberToWords(self, number):
  
              # Check if there is decimal in the number. If Yes process them as paisa part.
              formString = str(number)
              if formString.find('.') != -1:
                  withoutDecimal, decimalPart = formString.split('.')
  
                  paisaPart =  str(round(float(formString), 2)).split('.')[1]
                  inPaisa = self._formulateDoubleDigitWords(paisaPart)
  
                  formString, formNumber = str(withoutDecimal), int(withoutDecimal)
              else:
                  # Process the number part without decimal separately
                  formNumber = int(number)
                  inPaisa = None
  
              if not formNumber:
                  return 'zero'
  
              self._validateNumber(formString, formNumber)
  
              inRupees = self._convertNumberToWords(formString)
  
              if inPaisa:
                  return 'Rs. %s and %s paisa' % (inRupees.title(), inPaisa.title())
              else:
                  return 'Rs. %s' % inRupees.title()
  
  
          def _validateNumber(self, formString, formNumber):
  
              assert formString.isdigit()
  
              # Developed to provide words upto 999999999
              if formNumber > 999999999 or formNumber < 0:
                  raise AssertionError('Out Of range')
  
  
          def _convertNumberToWords(self, formString):
  
              MSBs, hundredthPlace, teens = self._getGroupOfNumbers(formString)
  
              wordsList = self._convertGroupsToWords(MSBs, hundredthPlace, teens)
  
              return ' '.join(wordsList)
  
  
          def _getGroupOfNumbers(self, formString):
  
              hundredthPlace, teens = formString[-3:-2], formString[-2:]
  
              msbUnformattedList = list(formString[:-3])
  
              #---------------------------------------------------------------------#
  
              MSBs = []
              tempstr = ''
              for num in msbUnformattedList[::-1]:
                  tempstr = '%s%s' % (num, tempstr)
                  if len(tempstr) == 2:
                      MSBs.insert(0, tempstr)
                      tempstr = ''
              if tempstr:
                  MSBs.insert(0, tempstr)
  
              #---------------------------------------------------------------------#
  
              return MSBs, hundredthPlace, teens
  
  
          def _convertGroupsToWords(self, MSBs, hundredthPlace, teens):
  
              wordList = []
  
              #---------------------------------------------------------------------#
              if teens:
                  teens = int(teens)
                  tensUnitsInWords = self._formulateDoubleDigitWords(teens)
                  if tensUnitsInWords:
                      wordList.insert(0, tensUnitsInWords)
  
              #---------------------------------------------------------------------#
              if hundredthPlace:
                  hundredthPlace = int(hundredthPlace)
                  if not hundredthPlace:
                      # Might be zero. Ignore.
                      pass
                  else:
                      hundredsInWords = '%s hundred' % self.wordsDict[hundredthPlace]
                      wordList.insert(0, hundredsInWords)
  
              #---------------------------------------------------------------------#
              if MSBs:
                  MSBs.reverse()
  
                  for idx, item in enumerate(MSBs):
                      inWords = self._formulateDoubleDigitWords(int(item))
                      if inWords:
                          inWordsWithDenomination = '%s %s' % (inWords, self.powerNameList[idx])
                          wordList.insert(0, inWordsWithDenomination)
  
              #---------------------------------------------------------------------#
              return wordList
  
  
          def _formulateDoubleDigitWords(self, doubleDigit):
  
              if not int(doubleDigit):
                  # Might be zero. Ignore.
                  return None
              elif self.wordsDict.has_key(int(doubleDigit)):
                  # Global dict has the key for this number
                  tensInWords = self.wordsDict[int(doubleDigit)]
                  return tensInWords
              else:
                  doubleDigitStr = str(doubleDigit)
                  tens, units = int(doubleDigitStr[0])*10, int(doubleDigitStr[1])
                  tensUnitsInWords = '%s %s' % (self.wordsDict[tens], self.wordsDict[units])
                  return tensUnitsInWords
  
  
  if __name__ == '__main__':
  
      wGenerator = Number2Words()
      print wGenerator.convertNumberToWords(100000)
  

Answer 2

You can use the python library num2words (pip install num2words):

Example:

from num2words import num2words
num2words(110543, to='cardinal', lang='en_IN')

Output:

'one lakh, ten thousand, five hundred and forty-three'