如何在Python中使用某些键来选择字典？

Question

我有这样的JSON data和大约100个问题。我如何筛选问题，最多只能筛选到40

这是数据样本：

data=[{"id": "AA11",
"resp": [
    {"answer": "A","number": 1},
    {"answer": "A","number": 2},
    {"answer": "B","number": 3},
    {"answer": "D","number": 4},
    {"answer": "E","number": 5}
]},
{"id": "AA22",
"resp": [
    {"answer": "A","number": 1},
    {"answer": "A","number": 2},
    {"answer": "B","number": 3},
    {"answer": "D","number": 4},
    {"answer": "E","number": 5}
]},
{"id": "AA33",
"resp": [
    {"answer": "A","number": 1},
    {"answer": "A","number": 2},
    {"answer": "B","number": 3},
    {"answer": "D","number": 4},
    {"answer": "E","number": 5}
]}]

在本例中，我是否可以仅提取数字3以下的数据作为示例

输出：

data=[{"id": "AA11",
"resp": [
    {"answer": "A","number": 1},
    {"answer": "A","number": 2},
    {"answer": "B","number": 3}
]},
{"id": "AA22",
"resp": [
    {"answer": "A","number": 1},
    {"answer": "A","number": 2},
    {"answer": "B","number": 3}
]},
{"id": "AA33",
"resp": [
    {"answer": "A","number": 1},
    {"answer": "A","number": 2},
    {"answer": "B","number": 3}
]}]

Answer 1

过滤到一个特定的元素应该可以这样做

def filter(question,num):
    temp = {}
    for key in question:
        temp[key] = question[key]
    temp['resp'] = question['resp'][:num]
    return temp

def filter_list(questions,num):
    temp = []
    for question in questions:
        temp.append(filter(question,num))
    return temp

data = [{}...]
filtered_data = filter_list(data)

您会注意到filter创建了question的副本，并且只更改了副本。更改数据结构可能很有用，但最好尽可能将数据结构视为不可变的

作为奖励，您不会以这种方式丢失任何原始数据

Answer 2

for item in data:
    item['resp'] = item['resp'][:3]

Answer 3

Python式的方式是一种理解：

filtered = [{'id': d['id'], 'resp': [x for x in d['resp'] if x['number'] <= 3]}
            for d in data]

正如预期的那样：

[{'id': 'AA11',
  'resp': [{'answer': 'A', 'number': 1},
           {'answer': 'A', 'number': 2},
           {'answer': 'B', 'number': 3}]},
 {'id': 'AA22',
  'resp': [{'answer': 'A', 'number': 1},
           {'answer': 'A', 'number': 2},
           {'answer': 'B', 'number': 3}]},
 {'id': 'AA33',
  'resp': [{'answer': 'A', 'number': 1},
           {'answer': 'A', 'number': 2},
           {'answer': 'B', 'number': 3}]}]