# 字典

# 1. 创建字典
# a = {}
# b = dict()

# 2. 设置初始值
# a = {'id': 1, 'name': "张三"}
# a = {
#     'id': 1,
#     'name': "张三"
# }
# print(a)

# 使用 in 判断某个 key 是否存在
# a = {
#     "name": "Jack",
#     "id": 1
# }
# print("id" in a)
# print("classId" not in a)

# 2. 使用 [] 根据 key 获取对应的 value
# a = {
#     "name": "Jack",
#     "id": 1
# }
# print(a["id"])
# print(a["name"])
# print(a["age"])  # 对应的 key 不存在, 抛异常

# [] 不存在就创建, 存在就修改

# 1. 利用 [] 添加元素
# a = {
#     "id": 1,
#     "name": "Jack"
# }
# a["score"] = 90
# print(a)

# 2. 利用 [] 根据 key 修改 value
# a = {
#     "id": 1,
#     "name": "Jack"
# }
# a["name"] = "Tom"
# print(a)

# 3. 利用 pop 删除对应的键值对
# a = {
#     "id": 1,
#     "name": "Jack",
#     "age": 18
# }
# print(a)
# a.pop("age")
# print(a)

# 4. 利用 for 循环遍历字典
# a = {
#     "id": 1,
#     "name": "Jack",
#     "age": 18
# }
# for key in a:
#     print(key, a[key])

a = {
    "id": 1,
    "name": "Jack",
    "age": 18
}
# 5. 获取字典中所有的 key
print(a.keys())
# 6. 获取字典中所有的 value
print(a.values())
# 7. 获取字典中所有的 key-value
print(a.items())

for key, value in a.items():
    print(key, value)