Javascript Lodash 按外部数组和内部属性排序

Question

我有一组人，我需要按定义的外部数组（顺序）然后按年龄进行排序。 我正在使用 lodash sortBy

const _  = require('lodash');
const arr = [
  { name: "Mandy", age: "34" },
  { name: "Shelly", age: "32" },
  { name: "Kyle", age: "12" },
  { name: "Kyle", age: "60" },
  { name: "Mandy", age: "32" },
  { name: "Mandy", age: "99" },
  { name: "Shelly", age: "30" },
  { name: "John", age: "3" },
  { name: "John", age: "1" },
  { name: "John", age: "6" },
  { name: "Mandy", age: "3" }
];

let order = ["Shelly", "John", "Mandy", "Kyle"];

let sortedArrByOrder = _.sortBy(arr, [person => order.indexOf(person.name), 'age'], ['asc', 'desc']);

console.log(sortedArrByOrder);

但是年龄不是按降序排列的。 有没有办法让它工作？

Answer 1

_.sortBy()除了 order (asc / desc)，使用_.orderBy()代替：

 const arr = [{ name: "Mandy", age: "34" },{ name: "Shelly", age: "32" },{ name: "Kyle", age: "12" },{ name: "Kyle", age: "60" },{ name: "Mandy", age: "32" },{ name: "Mandy", age: "99" },{ name: "Shelly", age: "30" },{ name: "John", age: "3" },{ name: "John", age: "1" },{ name: "John", age: "6" },{ name: "Mandy", age: "3" }]; const order = ["Shelly", "John", "Mandy", "Kyle"]; const sortedArrByOrder = _.orderBy(arr, [person => order.indexOf(person.name), 'age'], ['asc', 'desc']); console.log(sortedArrByOrder);

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.js"></script>

此外，在排序操作中使用Array.indexOf() (O(n)) (O(nLogn) 用于超过 10 个项目的数组)，可能会损害性能。 更好的方法是将order数组转换为具有 O(1) 检索的数据结构，如 Map 或普通 object，并存储数组中的原始索引。 现在可以直接获取原始索引：

 const arr = [{ name: "Mandy", age: "34" },{ name: "Shelly", age: "32" },{ name: "Kyle", age: "12" },{ name: "Kyle", age: "60" },{ name: "Mandy", age: "32" },{ name: "Mandy", age: "99" },{ name: "Shelly", age: "30" },{ name: "John", age: "3" },{ name: "John", age: "1" },{ name: "John", age: "6" },{ name: "Mandy", age: "3" }]; const order = new Map(["Shelly", "John", "Mandy", "Kyle"].map((s, i) => [s, i])) const sortedArrByOrder = _.orderBy(arr, [person => order.get(person.name), 'age'], ['asc', 'desc']); console.log(sortedArrByOrder);

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.js"></script>

Answer 2

您可以进行回调并返回负年龄并省略订单数组。

 const arr = [{ name: "Mandy", age: "34" }, { name: "Shelly", age: "32" }, { name: "Kyle", age: "12" }, { name: "Kyle", age: "60" }, { name: "Mandy", age: "32" }, { name: "Mandy", age: "99" }, { name: "Shelly", age: "30" }, { name: "John", age: "3" }, { name: "John", age: "1" }, { name: "John", age: "6" }, { name: "Mandy", age: "3" }], order = ["Shelly", "John", "Mandy", "Kyle"], sortedArrByOrder = _.sortBy(arr, [ ({ name }) => order.indexOf(name), ({ age }) => -age ]); console.log(sortedArrByOrder);

 .as-console-wrapper { max-height: 100%;important: top; 0; }

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.min.js"></script>

Answer 3

您可以使用带有||的普通 javascript 中的sort方法执行此操作操作员。 因此，您首先按顺序排序，然后按age排序。

 const arr = [{ name: "Mandy", age: "34" },{ name: "Shelly", age: "32" },{ name: "Kyle", age: "12" },{ name: "Kyle", age: "60" },{ name: "Mandy", age: "32" },{ name: "Mandy", age: "99" },{ name: "Shelly", age: "30" },{ name: "John", age: "3" },{ name: "John", age: "1" },{ name: "John", age: "6" },{ name: "Mandy", age: "3" }]; const order = ["Shelly", "John", "Mandy", "Kyle"]; arr.sort((a, b) => order.indexOf(a.name) - order.indexOf(b.name) || b.age - a.age) console.log(arr)