如何在 Python 字典的字典中引用？

Question

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如何在问题中引用topic键?我想在我的列表中搜索具有特定主题的所有问题，然后返回关于随机问题的所有信息。

然而，当使用下面的代码时，我得到一个错误说:

if question['topic'] == topic:
TypeError: 'int' object is not subscriptable

然而，如果我尝试将整数更改为字符串，我得到一个错误，说它们必须是整数。怎么解呢?

代码-这段代码应该将特定主题的所有问题添加到列表中，以便我可以在列表中使用随机函数来生成随机问题。

def random_question_in_topic(topic: str):
topic_questions = []
for question in questions:
if question['topic'] == topic:
topic_questions.append(question)

print(topic_questions)

提取从我的字典。(共30项)

questions = {
1 : {
'type': 'memory',
"topic": "literature",
"question": "Who wrote Twilight series of novels?",
"answer": "stephenie meyer",
},
2 : {
'type': 'memory',
"topic": "literature",
"question": "What was Frankenstein's first name?",
"answer": "jolly roger",
},
3 : {
'type': 'memory',
"topic": "general",
"question": "What is the only anagram of the word 'english'?",
"answer": "shingles",
},
4 : {
'type': 'memory',
"topic": "general",
"question": "Gala, Jonagold and Pink Lady are varieties of which fruit?",
"answer": "apple",
}
}

提前感谢!

我使用Python 3.8.12在Replit上。

Answer 1

for question in questions.values():
if question['topic'] == 'history':
print(question)
topic_questions.append(question)

感谢原帖的评论。

Answer 2

出现此错误是因为当您遍历字典时，您正在遍历它的键。让我们仔细看看。

如果运行以下代码

for question in questions:
print(question)

…您将得到以下输出:

1
2
3
4

所以，与其遍历键，不如遍历字典的值。为此，您可以使用dict对象的values()方法。因此，如果您尝试以下代码:

for question in questions.values():
print(question)

…您将得到如下输出:

{'type': 'memory', 'topic': 'literature', 'question': 'Who wrote Twilight series of novels?', 'answer': 'stephenie meyer'}
...

现在，变量question是一个对象，您可以对其使用索引，例如question['topic']。因此，代码可以重写为:

def random_question_in_topic(topic: str):
topic_questions = []
for question in questions.values():
if question['topic'] == topic:
topic_questions.append(question)

print(topic_questions)