Javascript 分组和排序

Question

我有如下随机城市列表。如何按照以下标准对其进行分组和排序

1. SortAndGroup 函数应该输入 countryCode 并相应地排序，每个组的首府城市排在第一位，然后是该国家/地区的城市。感谢您的帮助。

   随机城市 =

     [
            {
                "name": "Delhi",
                "countryCode": "IN",
                "isCapitol": true
            },
            {
                "name": "New York",
                "countryCode": "USA",
                "isCapitol": false
            },
            {
                "name": "Birmingham",
                "countryCode": "UK",
                "isCapitol": false
            },
            {
                "name": "London",
                "countryCode": "UK",
                "isCapitol": true
            },
            {
                "name": "Hyderabad",
                "countryCode": "IN",
                "isCapitol": false
            },
            {
                "name": "Chicago",
                "countryCode": "USA",
                "isCapitol": false
            },
            {
                "name": "Bristol",
                "countryCode": "UK",
                "isCapitol": false
            },
            {
                "name": "Washington",
                "countryCode": "USA",
                "isCapitol": true
            }
        ]
   

   最终结果应该是

   sortByCountry（美国、英国、印度）=

    [
        {
            "name": "Washington",
            "countryCode": "USA",
            "isCapitol": true
        },
        {
            "name": "Chicago",
            "countryCode": "USA",
            "isCapitol": false
        },
        {
            "name": "New York",
            "countryCode": "USA",
            "isCapitol": false
        },
        {
            "name": "London",
            "countryCode": "UK",
            "isCapitol": true
        },
        {
            "name": "Birmingham",
            "countryCode": "UK",
            "isCapitol": false
        },
        {
            "name": "Bristol",
            "countryCode": "UK",
            "isCapitol": false
        },
        {
            "name": "Delhi",
            "countryCode": "IN",
            "isCapitol": true
        },
        {
            "name": "Hyderabad",
            "countryCode": "IN",
            "isCapitol": false
        } 
    ]
   

Answer 1

您可以从数组中获取订单（带有相应的国家名称）并按首都排序。

const
    sortByCountry = (...countries) => (a, b) =>
        countries.indexOf(a.countryCode) - countries.indexOf(b.countryCode) ||
        b.isCapitol - a.isCapitol,
    array = [{ name: "Delhi", countryCode: "IN", isCapitol: true }, { name: "New York", countryCode: "USA", isCapitol: false }, { name: "Birmingham", countryCode: "UK", isCapitol: false }, { name: "London", countryCode: "UK", isCapitol: true }, { name: "Hyderabad", countryCode: "IN", isCapitol: false }, { name: "Chicago", countryCode: "USA", isCapitol: false }, { name: "Bristol", countryCode: "UK", isCapitol: false }, { name: "Washington", countryCode: "USA", isCapitol: true }];

array.sort(sortByCountry('USA', 'UK', 'IN'));

console.log(array);

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ES5

var sortByCountry = function () {
        var countries = Array.prototype.slice.call(arguments);
        return function (a, b) {
            return countries.indexOf(a.countryCode) - countries.indexOf(b.countryCode) ||
                b.isCapitol - a.isCapitol;
        }
    },
    array = [{ name: "Delhi", countryCode: "IN", isCapitol: true }, { name: "New York", countryCode: "USA", isCapitol: false }, { name: "Birmingham", countryCode: "UK", isCapitol: false }, { name: "London", countryCode: "UK", isCapitol: true }, { name: "Hyderabad", countryCode: "IN", isCapitol: false }, { name: "Chicago", countryCode: "USA", isCapitol: false }, { name: "Bristol", countryCode: "UK", isCapitol: false }, { name: "Washington", countryCode: "USA", isCapitol: true }];

array.sort(sortByCountry('USA', 'UK', 'IN'));

console.log(array);

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

Answer 2

您可以使用Array.prototype.sort() 方法来完成此操作，并通过创建一个排序数组对国家代码进行排序，然后按大写字母，最后按城市名称。

const sortByCountry = (data, order) =>
  data.sort(
    (x, y) =>
      order.indexOf(x.countryCode) - order.indexOf(y.countryCode) ||
      y.isCapitol - x.isCapitol ||
      x.name.localeCompare(y.name)
  );
const data = [
  {
    name: 'Delhi',
    countryCode: 'IN',
    isCapitol: true,
  },
  {
    name: 'New York',
    countryCode: 'USA',
    isCapitol: false,
  },
  {
    name: 'Birmingham',
    countryCode: 'UK',
    isCapitol: false,
  },
  {
    name: 'London',
    countryCode: 'UK',
    isCapitol: true,
  },
  {
    name: 'Hyderabad',
    countryCode: 'IN',
    isCapitol: false,
  },
  {
    name: 'Chicago',
    countryCode: 'USA',
    isCapitol: false,
  },
  {
    name: 'Bristol',
    countryCode: 'UK',
    isCapitol: false,
  },
  {
    name: 'Washington',
    countryCode: 'USA',
    isCapitol: true,
  },
];
const order = ['IND', 'USA', 'UK'];
console.log(sortByCountry(data, order));

Answer 3

为了对数组进行排序，可以使用：

arr.sort([compareFunction])

所以你必须编写一个自定义的 compareFunction

compareFunction 比较数组的任意两个元素，如果第一个元素“更大”则返回 1，如果第一个元素“更小”则返回 -1

arr.sort((a, b) => (a > b) ? 1 : -1)

在这种情况下，我们的排序函数可以接收任意数量的参数，因此我们可以在 arguments 对象中访问它们。我们可以将arguments对象转换成一个数组，并使用indexOf函数来比较国家代码在数组中的位置。

当国家代码相同时，我们检查其中一项是否为capitol。

randomCities =
  [
         {
             "name": "Delhi",
             "countryCode": "IN",
             "isCapitol": true
         },
         {
             "name": "New York",
             "countryCode": "USA",
             "isCapitol": false
         },
         {
             "name": "Birmingham",
             "countryCode": "UK",
             "isCapitol": false
         },
         {
             "name": "London",
             "countryCode": "UK",
             "isCapitol": true
         },
         {
             "name": "Hyderabad",
             "countryCode": "IN",
             "isCapitol": false
         },
         {
             "name": "Chicago",
             "countryCode": "USA",
             "isCapitol": false
         },
         {
             "name": "Bristol",
             "countryCode": "UK",
             "isCapitol": false
         },
         {
             "name": "Washington",
             "countryCode": "USA",
             "isCapitol": true
         }
     ]

function sortByCountry(){
  var args = Array.from(arguments);
  randomCities.sort( (a, b) => (args.indexOf(a.countryCode) == args.indexOf(b.countryCode)) ? (a.isCapitol ? -1 : 1) : ((args.indexOf(a.countryCode) > args.indexOf(b.countryCode)) ? 1 : -1));
  return randomCities;
}

sortyByCountry('USA', 'UK', 'IN');