如何将多个值传递到字典中

Question

所以我有以下代码：

    {'stu_name': 'Abel', 'sex': 'male', 'score': 90, 'cls_id': 1},
    {'stu_name': 'Carl', 'sex': 'male', 'score': 80, 'cls_id': 2},
    {'stu_name': 'Cecil', 'sex': 'female', 'score': 60, 'cls_id': 1},
    {'stu_name': 'Elijah', 'sex': 'female', 'score': 70, 'cls_id': 2},
    {'stu_name': 'Dick', 'sex': 'male', 'score': 90, 'cls_id': 3},
    {'stu_name': 'Donald', 'sex': 'male', 'score': 80, 'cls_id': 3},
    {'stu_name': 'Jack', 'sex': 'male', 'score': 80, 'cls_id': 2},
    {'stu_name': 'Laurent', 'sex': 'female', 'score': 90, 'cls_id': 1},
    {'stu_name': 'Rex', 'sex': 'female', 'score': 90, 'cls_id': 1},
    {'stu_name': 'Tom', 'sex': 'male', 'score': 70, 'cls_id': 2},
    {'stu_name': 'Roy', 'sex': 'female', 'score': 90, 'cls_id': 3},
    {'stu_name': 'Steve', 'sex': 'male', 'score': 70, 'cls_id': 1}
]
cls_list = [
    {'id': 1, 'cls_name': 'Class One'},
    {'id': 2, 'cls_name': 'Class Two'},
    {'id': 3, 'cls_name': 'Class Three'},
    {'id': 4, 'cls_name': 'Class Four'}
]

我想要的是将程序 output 命名为 class 名称，然后是其中的人数，然后是其中的男性人数，最后是女性人数。 我到目前为止是这样的：

lst_empty = {}
for cls in cls_list:
    lst_empty.setdefault(cls['cls_name'], 0)
    for stu in stu_list:
      if stu['cls_id'] == cls['id']:
          lst_empty[cls['cls_name']] +=1
      if stu['sex'] == 'male':

因为 setdefault 只能给我 2 件物品，所以我有点纠结于如何处理 if sex = male 位。 我想我的主要问题是如何将男性数量传递到空字典中。 我不想彻底改变我的代码，我只想知道我现在可以用我的代码做什么。 谢谢！

Answer 1

我已将lst_empty作为字典列表。 代码如下：

stu_list = [{'stu_name': 'Abel', 'sex': 'male', 'score': 90, 'cls_id': 1},
            {'stu_name': 'Carl', 'sex': 'male', 'score': 80, 'cls_id': 2},
            {'stu_name': 'Cecil', 'sex': 'female', 'score': 60, 'cls_id': 1},
            {'stu_name': 'Elijah', 'sex': 'female', 'score': 70, 'cls_id': 2},
            {'stu_name': 'Dick', 'sex': 'male', 'score': 90, 'cls_id': 3},
            {'stu_name': 'Donald', 'sex': 'male', 'score': 80, 'cls_id': 3},
            {'stu_name': 'Jack', 'sex': 'male', 'score': 80, 'cls_id': 2},
            {'stu_name': 'Laurent', 'sex': 'female', 'score': 90, 'cls_id': 1},
            {'stu_name': 'Rex', 'sex': 'female', 'score': 90, 'cls_id': 1},
            {'stu_name': 'Tom', 'sex': 'male', 'score': 70, 'cls_id': 2},
            {'stu_name': 'Roy', 'sex': 'female', 'score': 90, 'cls_id': 3},
            {'stu_name': 'Steve', 'sex': 'male', 'score': 70, 'cls_id': 1}]

cls_list = [{'id': 1, 'cls_name': 'Class One'},
            {'id': 2, 'cls_name': 'Class Two'},
            {'id': 3, 'cls_name': 'Class Three'},
            {'id': 4, 'cls_name': 'Class Four'}]

lst_empty = []
for cls in cls_list:
    dct = {}

    dct.setdefault(cls['cls_name'], 0)
    dct.setdefault('male', 0)
    for stu in stu_list:
        if stu['cls_id'] == cls['id']:
            dct[cls['cls_name']] +=1
            if stu['sex'] == 'male':
                dct["male"] += 1
    dct["female"] = dct[cls["cls_name"]] - dct["male"]

    lst_empty.append(dct)

for i in lst_empty:
    print(i)

output 是：

{'Class One': 5, 'male': 2, 'female': 3}
{'Class Two': 4, 'male': 3, 'female': 1}
{'Class Three': 3, 'male': 2, 'female': 1}
{'Class Four': 0, 'male': 0, 'female': 0}

Answer 2

最简单但并不理想的解决方案是：

for cls in cls_list:
    cls_students = list(filter(lambda s: s['cls_id'] == cls['id'], stu_list))
    cls_males    = list(filter(lambda s: s['sex']    == 'male'   , cls_students))
    cls_females  = list(filter(lambda s: s['sex']    == 'female' , cls_students))
    print(cls['cls_name'])
    print(f"Total students: {len(cls_students)}")
    print(f"Num of males:   {len(cls_males)   }")
    print(f"Num of females: {len(cls_females) }")

但是您最好考虑pandas库及其方便的DataFrame s

Answer 3

只需使用dict.get ：

dct = {}

for stu in stu_list:
    if stu['cls_id'] == cls['id']:
        dct[cls['cls_name']] = dct.get(cls['cls_name'], 0) + 1
        # will handle both 'male' and 'female' cases
        dct[stu['sex']] = dct.get(stu['sex'], 0) + 1

lst_empty.append(dct)

Answer 4

您可以 setdefault 一个空列表或另一个字典。

lst_empty.setdefault(cls['cls_name'], [0, 0, 0]) 

或者

lst_empty.setdefault(cls['cls_name'], {"nb_people" : 0, "nb_male" : 0, "nb_female" : 0})

Answer 5

如果您希望将结果顶部存储在字典中，您可以这样做：

cls_dict = {}


for cls in cls_list:
    cls_dict[cls['id']]={}
    cls_dict[cls['id']]['id']=cls['id']
    cls_dict[cls['id']]['cls_name']=cls['cls_name']
    cls_dict[cls['id']]['population']=0
    cls_dict[cls['id']]['males']=0
    cls_dict[cls['id']]['females']=0


for stu in stu_list:
    if stu['cls_id'] in cls_dict:
        id = stu['cls_id']
        if stu['sex']=='female':
            cls_dict[id]['females']+=1
            cls_dict[id]['population']+=1
        elif stu['sex']=='male':
            cls_dict[id]['males']+=1
            cls_dict[id]['population']+=1
            

print(cls_dict)

output 将是：

{1: {'id': 1, 'cls_name': 'Class One', 'population': 5, 'males': 2, 'females': 3},
 2: {'id': 2, 'cls_name': 'Class Two', 'population': 4, 'males': 3, 'females': 1},
 3: {'id': 3, 'cls_name': 'Class Three', 'population': 3, 'males': 2, 'females': 1},
 4: {'id': 4, 'cls_name': 'Class Four', 'population': 0, 'males': 0, 'females': 0}}