python - 在 Python 中，如何让用户选择要更新的键然后选择新值来更新字典值？

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册中输入和编辑信息，以比较球队和管理球员等。这是我尝试过的第一个“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。但是当我尝试让“用户”(通过 raw_input)返回编辑它们时，我被卡住了。下面我试着把我认为与我的错误相关的代码的简化版本写下来。如果我需要放下完整版本，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……”等时，我的意思是说“我想要它给……”

总而言之，我希望用户选择要编辑的球员，选择要编辑的数据，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，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，Python 对名称的赋值通常不会复制对象，而只会为相同 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}
>>>