如何在python中访问这些json对象？

import json

json_str = '{"name": "John", "age": 30, "city": "New York"}'
json_obj = json.loads(json_str)

print(json_obj["name"])  # 访问name字段的值
print(json_obj["age"])  # 访问age字段的值
print(json_obj["city"])  # 访问city字段的值

John
30
New York

import json

json_str = '{"person": {"name": "John", "age": 30, "city": "New York"}}'
json_obj = json.loads(json_str)

print(json_obj["person"]["name"])  # 访问嵌套的name字段的值
print(json_obj["person"]["age"])  # 访问嵌套的age字段的值
print(json_obj["person"]["city"])  # 访问嵌套的city字段的值

John
30
New York

import json

person = {
    "name": "John",
    "age": 30,
    "city": "New York"
}

json_str = json.dumps(person)
print(json_str)

{"name": "John", "age": 30, "city": "New York"}