从变量键中提取特定属性

const user = {
  name: 'John',
  age: 25,
  email: 'john@example.com',
  address: {
    street: '123 Main St',
    city: 'New York',
    state: 'NY'
  }
};

const { name } = user;
console.log(name); // 输出：John

const { address: { city } } = user;
console.log(city); // 输出：New York

user = {
  'name': 'John',
  'age': 25,
  'email': 'john@example.com',
  'address': {
    'street': '123 Main St',
    'city': 'New York',
    'state': 'NY'
  }
}

name = user['name']
print(name)  # 输出：John

city = user['address']['city']
print(city)  # 输出：New York