old_contents: # This program returns True if a string is a phone number and False if not
  # However, it's not very efficient
  
  
  def isPhoneNumber(text):
      if len(text) != 12:
          return False
      for i in range(0, 3):
          if not text[i].isdecimal():
              return False
      if text[3] != '-':
          return False
      for i in range(4, 7):
          if not text[i].isdecimal():
              return False
      if text[7] != '-':
          return False
      for i in range(8, 12):
          if not text[i].isdecimal():
              return False
      return True
  
  
  print('415-555-4242 is a phone number:')
  print(isPhoneNumber('415-555-4242'))
  print('Moshi moshi is a phone number:')
  print(isPhoneNumber('Moshi moshi'))
  
new_contents: # This program returns True if a string is a phone number and False if not
  # However, it's not very efficient
  
  
  def isPhoneNumber(text):
      if len(text) != 12:
          return False
      for i in range(0, 3):
          if not text[i].isdecimal():
              return False
      if text[3] != '-':
          return False
      for i in range(4, 7):
          if not text[i].isdecimal():
              return False
      if text[7] != '-':
          return False
      for i in range(8, 12):
          if not text[i].isdecimal():
              return False
      return True
  
  
  print('415-555-4242 is a phone number:')
  print(isPhoneNumber('415-555-4242'))
  print('Moshi moshi is a phone number:')
  print(isPhoneNumber('Moshi moshi'))
  
  message = 'Call me at 415-555-1011 tomorrow. 415-555-9999 is my office.'
  for i in range(len(message)):
      chunk = message[i:i + 12]
      if isPhoneNumber(chunk):
          print('Phone number found: ' + chunk)
  print('Done')
  
subject: Update P01_isPhoneNumber: adds sample string parser