Python列表pop

Question

我有一个名为all_questions的列表

all_questions={
{
    'question': "Mac and Pc share which of the following things:",
    'answer1': "They are both expensive",
    'answer2': "They are both Touch Screen",
    'answer3': "Intel is now inside both computers",
    'answer4': "They both have good security",
    'correct_answer': 3,
  },
  {
    'question': "Who was the other person that co-founded Microsoft:",
    'answer1': "Bill Gates",
    'answer2': "Nathan Myhrvold",
    'answer3': "Paul Allen",
    'answer4': "Richard Rashid",
    'correct_answer': 3,
  },
  {
    'question': "When did Windows 10 come out:",
    'answer1': "July 29,2015",
    'answer2': "July 30,2015",
    'answer3': "July 28,2015",
    'answer4': "It was not released in July",
    'correct_answer': 1,
  }
    }

名单上有问题和答案。我试着做一个提示按钮，删除随机按钮，取出正确的答案。提示按钮的代码是：

def hint_btn():
    choices=[choice1,choice2,choice3,choice4]
    q = all_questions[current_question]
    h = [('correct_answer', 1), ('correct_answer', 2), ('correct_answer', 3), ('correct_answer', 4)]
    f = all_questions.popitem()
    h = choices.pop(choices.index(f))    
    false_answer = random.choice(choices)
    false_answer2 = random.choice(choices)

    if (random.random() > 0.5):
        hint1 = choices[q['correct_answer']]
        hint1.pack()
        hint_btn()
        hint2 = choices[false_answer]
        hint2.pack_forget()
        hint3 = choices[false_answer2]
        hint3.pack_forget()
        choices.append(h)

但是，我说错了：

TypeError: unhashable type: 'dict' for 'correct_answer': 1

Answer 1

这个错误意味着您正在做这样的事情：

dictionary[key]

..。其中key是一个“不可理解的类型”。字典的关键必须是“可理解的”(本质上，一些不能改变的东西--即:字符串、元组、数字等等)。

在您的例子中，您试图创建一个字典(all_questions)，其中字典作为键。一个简单的解决方案可能是将all_questions变成列表而不是字典(注意使用方括号而不是花括号)：

all_questions = [
    {
        'question': "Mac and Pc share which of the following things:",
        'answer1': "They are both expensive",
        'answer2': "They are both Touch Screen",
        ...
    },
    {
        ...
    },
    ...
]

有关“哈斯可类型”含义的更多信息，请参见以下问题：Hashable, immutable

您似乎在努力解决这个问题，我已经看到了两个或三个问题，它们都涉及到相同的数据结构。我建议你重新考虑你的数据结构。如果您在试图处理某些数据时遇到困难，有时解决方案是更改数据，以便更容易地操作。

你想要一个问题，一个正确的答案，和一些不正确的答案，这样你就可以在屏幕上呈现它们。您还希望能够在某个时间点随机删除不正确的答案。对，是这样?对我来说，这意味着你的正确和不正确的答案应该存储在单独的实体中。

交替解一

您可能需要考虑将不正确的答案放在列表中，并单独保留正确的答案。例如：

all_questions = [
    {
        "question": "Mac and Pc share which of the following things:",
        "correct answer": "Intel is now inside both computers",
        "incorrect answers": [
            "They are both expensive",
            "They are both Touch Screen",
            "They both have good security",
        ],
    },
    ...
]

要为第一个问题创建一个所有答案的列表，您可以这样做：

q = all_questions[0]
answers = q["incorrect answers"]
answers.append(q["correct answer"])
random.shuffle(answers)

有了以上所述，answers现在是所有可能的答案的列表，但按随机顺序排列。

要删除两个随机不正确的答案，以便您有一个正确的和两个不正确的答案，同样按随机顺序，您可以这样做：

answers = random.sample(q["incorrect answers"], 2)
answers.append(q["correct answer"])
random.shuffle(answers)

在任何一种情况下，当用户选择一个答案时，您可以很容易地将其与正确的答案进行比较：

if user_answer == q["correct answer"]:
    print "correct!"
else
    print "incorrect"

交替解决方案2

请注意，以上并不一定是最好的方法。有很多种选择。例如，问题可以是字典键，值可以是包含正确答案的列表。例如：

all_questions = {
    "Mac and Pc share which of the following things": [
        "They both have intel inside",
        "They are both expensive",
        "They are both Touch Screen",
        "They both have good security"
    ]
}

这样，要删除两个随机项，首先删除正确的答案并将其保存到一个变量中。然后随机删除两个项目，并将它们与正确的答案结合起来。

数据结构很重要

关键是，数据结构很重要。考虑一下您需要如何访问数据，并对数据进行结构化，这样就很容易了。在这种情况下，您需要能够轻松地获得正确的答案，并且需要能够轻松地从不正确的答案列表中删除随机项。定义你的结构，使之变得简单。