如果key是数组，如何查找key的值？

const obj = {
  'a': 1,
  'b': 2,
  'c': 3
};

const keys = ['a', 'c'];

const values = keys.map(key => obj[key]);
console.log(values); // 输出: [1, 3]

const obj = {
  'a': 1,
  'b': 2,
  'c': 3
};

const keys = ['a', 'c'];

const sum = keys.reduce((accumulator, key) => accumulator + (obj[key] || 0), 0);
console.log(sum); // 输出: 4

const obj = {
  'a': 1,
  'b': 2,
  'c': 3
};

const keys = ['a', 'c'];

for (const key of keys) {
  console.log(obj[key]); // 分别输出: 1, 3
}

const obj = {
  'a': 1,
  'b': 2,
  'c': 3
};

const keys = ['a', 'c'];
const values = {};

for (const key in obj) {
  if (keys.includes(key)) {
    values[key] = obj[key];
  }
}

console.log(values); // 输出: { a: 1, c: 3 }