Python：基于嵌套字典值筛选并追加元素至列表的问题

需求：编写Python代码展示用户可选对象列表，每个对象带Size属性，初始总限额为5，选中对象后从剩余限额扣除对应Size值；后续仅显示Size不超过剩余限额的对象（如剩余限额2时，不显示Size为3的对象），目前其他功能正常，仅过滤功能未实现。

原始代码（标注待完善位置）：

set1_items = {
    "Option1": {
        "Common": [
            {"Item Name": "A1", "Size": 3},
            {"Item Name": "A2", "Size": 4}
        ],
        "Uncommon": [
            {"Item Name": "B1", "Size": 2},
            {"Item Name": "B2", "Size": 1}
        ]
    },
    "Option2": {
        "Common": [
            {"Item Name": "C1", "Size": 3},
            {"Item Name": "C2", "Size": 1}
        ],
        "Uncommon": [
            {"Item Name": "D1", "Size": 2},
            {"Item Name": "D2", "Size": 4}
        ]
    }
}

chosen_objects = []

objects_chosen = None
max_amount_limit = 5
selected_objects_size = 0
available_objects_list = []

while objects_chosen is None:
    if (max_amount_limit - selected_objects_size) > 3:
        available_objects_list = set1_items["Option1"]["Common"]
    elif (max_amount_limit - selected_objects_size) <4:
        available_objects_list = set1_items["Option1"]["Common"]?????

    object_availability = available_objects_list
    objects_itr = 0
    for i in object_availability:
        print(object_itr, end=' - ')
        for key, val in i.items():
            print(key, ": ", val, end='\n    ')
        print()
        object_itr = object_itr+1

    chosen_object_index = input("> ")
    chosen_object_index = int(chosen_object_index)
    chosen_objects.append(object_availability[chosen_object_index]["Item Name"])

    selected_objects_size = selected_objects_size + object_availability[chosen_object_index]["Size"]

    if max_amount_limit == selected_objects_size:
        objects_chosen = "Done"
    else:
        continue_object_selection = input("""
You have """+str(int(max_amount_limit - selected_objects_size))+""" amounts left.

Do you want to select more objects from Set 1, or move on to Set 2?
1 - Continue with Set 1
2 - Move on to Set 2

>""")

        if continue_object_selection == "1":
            objects_chosen = None
        elif continue_object_selection == "2":
            objects_chosen = "Done"
        else:
            print("Not a valid choice, try again")

核心是通过列表推导式对嵌套字典中的对象列表进行过滤，保留Size不超过剩余限额的元素。

修改后的关键代码部分：

while objects_chosen is None:
    # 计算当前剩余限额
    remaining_limit = max_amount_limit - selected_objects_size
    # 筛选Set1 Option1中所有Size <= 剩余限额的对象（可按需合并Common/Uncommon）
    available_objects_list = [
        item 
        for category in set1_items["Option1"].values() 
        for item in category 
        if item["Size"] <= remaining_limit
    ]

    # 后续原有代码保持不变...

说明： #

1. 先计算remaining_limit得到当前剩余限额，避免重复计算；
2. 用嵌套循环的列表推导式遍历set1_items["Option1"]下的所有分类（Common/Uncommon），再遍历每个分类里的对象；
3. 通过if item["Size"] <= remaining_limit筛选符合条件的对象，自动生成过滤后的列表。

如果只需筛选Common分类，可简化为：

available_objects_list = [
    item 
    for item in set1_items["Option1"]["Common"] 
    if item["Size"] <= remaining_limit
]

替换原始代码中available_objects_list的赋值逻辑，即可实现动态过滤功能。

内容的提问来源于stack exchange，提问作者Moonlyte Demon