有類的詞典？

Question

在Python中是否可以通過字典實例化一個類？

shapes = {'1':Square(), '2':Circle(), '3':Triangle()} 

x = shapes[raw_input()] 

我想讓從菜單中的用戶挑選，而不是代碼龐大，如果輸入else語句。例如，如果用戶輸入2，那麼x將是Circle的新實例。這可能嗎？

Answer 1

差不多。你想要的是

shapes = {'1':Square, '2':Circle, '3':Triangle} # just the class names in the dict 

x = shapes[raw_input()]() # get class from dict, then call it to create a shape instance. 

Answer 2

我推薦一個選擇器功能：

def choose(optiondict, prompt='Choose one:'): 
    print prompt 
    while 1: 
     for key, value in sorted(optiondict.items()): 
      print '%s) %s' % (key, value) 
     result = raw_input() # maybe with .lower() 
     if result in optiondict: 
      return optiondict[result] 
     print 'Not an option' 

result = choose({'1': Square, '2': Circle, '3': Triangle})()