def isPhoneNumber(text): if len(text) != 12: return False # not phone number-sized for i in range(0, 3): if not text[i].isdecimal(): return False # not an area code if text[3] != '-': return False # does not have first hyphen for i in range(4, 7): if not text[i].isdecimal(): return False # does not have first 3 digits if text[7] != '-': return False # does not have second hyphen for i in range(8, 12): if not text[i].isdecimal(): return False # does not have last 4 digits return True # "text" is a phone number! print('415-555-4242 is a phone number:') print(isPhoneNumber('415-555-4242')) print('Moshi moshi is a phone number:') print(isPhoneNumber('Moshi moshi'))