Question

1>创建一个嵌套词典，其中包含您在秋季和春季学期中今年正在做的学科的学科编号。换句话说，您应该有一个带有2个键的字典“秋天”和“春天”，并且与这些键关联的值本身应该是字典，其中键是主题编号，值是主题名称。

2>编写一个for循环，打印出您在秋天参加的科目编号。

这就是我所拥有的

my_subjects = {"Autumn": {37315:"Data", 34567:"Sci"}, "Spring": {23456:"Eng", 45879:"Math"}}

for season, season.subjects in my_subjects.items():
    print("\n Autumn Subject Numbers", season)

    for key in season.subjects:
        print(key)

但收到错误

AttributeError                            Traceback (most recent call last)
<ipython-input-208-b1fceae351e6> in <module>()
      5 
      6 
----> 7 for season, season.subjects in my_subjects.items():
      8     print("\n Autumn Subject Numbers", season)
      9 

AttributeError: 'str' object has no attribute 'subjects'

Answer 1

使用public class ParentController { private DataManager dataManager = new DataManager(); private ChildController childController1; private ChildController childController2; public void initializeChild() { childController1.setDataManager(dataManager); childController2.setDataManager(dataManager); // Controllers for different FXML Files // } } public class ChildController { /* Child controller has elements which need data from the DataManager */ private DataManager dataManager; public void setDataManager(DataManager dataManager) { this.dataManager = dataManager; } }中的.运算符，您正在尝试访问season.subjects对象的subjects属性，该属性没有这样的属性。您应该将season返回的元组中第二个项目的值分配给一个单独的变量：

my_subjects.items()

这将输出：

for season, subjects in my_subjects.items():
    if season == 'Autumn':
        print("Autumn Subject Numbers:", ', '.join(map(str, subjects)))

Answer 2

尝试一下

my_subjects = {"Autumn": {37315:"Data", 34567:"Sci"}, "Spring": {23456:"Eng", 45879:"Math"}}

for season, data in my_subjects.items():
    print("\n Autumn Subject Numbers", season)

    for key in data:
        print(key)

Answer 3

如何？

new_dict = {}

for k, v in my_subjects.items():
    for x, z in v.items():
        if k not in new_dict:
            new_dict[k] = [x]
        else:
            new_dict[k].append(x)
print(new_dict)

{'Autumn': [37315, 34567], 'Spring': [23456, 45879]}

编写一个for循环，打印1个嵌套字典的键

但收到错误

3 个答案: