如何在Python中更新字典值，让用户选择要更新的密钥，然后选择新值？

Question

我正在尝试编写一个程序，我和我的兄弟可以从我们的足球比赛名单中输入和编辑信息来比较球队和管理球员等。这是我尝试的第一个“大”项目。

我在字典中有一个嵌套字典，我能够让用户创建字典等。但是当我尝试使用'user'（通过raw_input）返回编辑它们时，我会卡住。 下面我尝试将代码的简化版本放在我认为与我的错误相关的内容之下。 如果我需要记下完整版，请告诉我。

player1 = {'stat1' : A, 'stat2' : 2, 'stat3' : 3} #existing players are the dictionaries 
player2 = {'stat1' : A, 'stat2' : 2, 'stat3' : 3} # containing the name of stat and its value
position1 = {'player1' : player1} # in each position the string (name of player) is the key and
position2 = {'player2' : player2} # the similarly named dict containing the statisics is the value
position = raw_input('which position? ') # user chooses which position to edit
if position == 'position1':
  print position1 # shows user what players are available to choose from in that position
  player = raw_input('which player? ') #user chooses player from available at that position
  if player == player1:
    print player # shows user the current stats for the player they chose
    edit_query = raw_input('Do you need to edit one or more of these stats? ')
    editloop = 0
    while editloop < 1: # while loop to allow multiple stats editing
      if edit_query == 'yes': 
        stat_to_edit = raw_input('Which stat? (If you are done type "done") ')
          if stat_to_edit == 'done': #end while loop for stat editing
            editloop = editloop +1
          else:
            new_value = raw_input('new_value: ') #user inserts new value

# up to here everything is working. 
# in the following line, player should give the name of the
# dictionary to change (either player1 or player2) 
# stat_to_edit should give the key where the matching value is to be changed
# and new_value should update the stastic
# however I get TypeError 'str' object does not support item assignment

            player[stat_to_edit] = new_value #update statistic
      else:  # end loop if no stat editing is wanted
        fooedit = fooedit + 1

当然，当我说“应该给......”等我的意思是说“我希望它给......”

总之，我希望用户选择要编辑的播放器，选择要编辑的统计数据，然后选择新值

Answer 1

问题似乎在这一行之后

player = raw_input('which player? ')

player将是字符串，包含用户输入的内容，而不是字典，如player1 。 这解释了为什么Python无法分配给它的部分。 你可以这样写：

player = raw_input('which player? ')
if player == 'player1': # these are strings!
  current_player = player1 # this is dictionary!
  ....
  current_player[...] = ... # change the dictionary

另请注意，对名称的Python赋值通常不会复制对象，而只会为同一现有对象添加另一个名称。 考虑这个例子（来自Python控制台）：

>>> a = {'1': 1}
>>> a
{'1': 1}
>>> b = a
>>> b
{'1': 1}
>>> b['1'] = 2
>>> b
{'1': 2}
>>> a
{'1': 2}
>>>