Python使用字典实现的简单记事本功能示例

from time import sleep, strftimeuser = "Cytus"calendar = {}def welcome():  print "Welcome to use this calendar. %s" % user  print "Calendar is opening."  sleep(1)  print strftime("%A %B %d %Y")  print strftime("%H:%M:%S")  sleep(1)  print "What would you like to do?"def start_calendar():  welcome()  start = True  while start:    user_choice = raw_input("A to add, U to Update, V to View, D to Delete, X to Exit: ")    user_choice = user_choice.upper()    if user_choice == "V":      if len(calendar.keys()) < 1:        print "The calendar is empty."      else:        print calendar    elif user_choice == "U":      date = raw_input("What date? ")      update = raw_input("Enter the update: ")      calendar[date] = update      print "Update successful."      print calendar    elif user_choice == "A":      event = raw_input("Enter event: ")      date = raw_input("Enter date (MM/DD/YYYY): ")      if (len(date) > 10) or int(date[6:]) < int(strftime("%Y")):        print "invaild date."        try_again = raw_input("Try again? Y for yes, N for No: ")        try_again = try_again.upper()        if try_again == "Y":          continue        else:          start = False      else:        calendar[date] = event        print "Successfully added."        print calendar    elif user_choice == "D":      if len(calendar.keys()) < 1:        print "The calendar is empty."      else:        event = raw_input("What event? ")        for date in calendar.keys():          if calendar[date] == event:            del calendar[date]            print "Delete successfully."            print calendar          else:            print "incorrect event was specified."    elif user_choice == "X":      start = False    else:      print "invalid input."      start = Falsestart_calendar()