javascript - 按 3 个属性对 javascript 数组进行排序

Question

我有一个包含位置列表的数组。

我添加了 3 个属性，详细说明每个位置与设定的起始位置的关系。

数组中的每个位置都有以下 3 个属性:

bearing (0 to 360 degrees)
humanFriendlyCompassHeading (North, North East, East etc)
distance (in km)

我能够按方位对数组进行排序，以便位置从 0 到 360 度列出，并且人类友好的罗盘标题按顺序排列，因此数组中的前几个条目是北，其次是东北、东等。

但是，我希望将每个人类友好的罗盘方向(即北、东北、东)的距离从最近到最远进行排序。

这是我迄今为止使用下面提供的代码和比较函数所得到的结果:

var myCmp = composeComparisons([sortArrayByBearing, sortArrayByHumanFriendlyCompassHeading, sortArrayByDistance]);
res.geonames.sort(myCmp);


function sortArrayByDistance(A, B)
{
return parseFloat(A.distance) - parseFloat(B.distance);
}

function sortArrayByBearing(A, B)
{
return parseFloat(A.bearing) - parseFloat(B.bearing);
}

//Used to sort results array by humanFriendlyCompassHeading
//usage: results.sort(sortArrayByHumanFriendlyCompassHeading);
//The sorting of humanFriendlyCompassHeading is realised with a map and look up for the value.
function sortArrayByHumanFriendlyCompassHeading(A, B) {
var DIRECTIONS = { North: 0, NorthEast: 1, East: 2, SouthEast: 3, South: 4, SouthWest: 5, West: 6, NorthWest: 7};
return         DIRECTIONS[A.humanFriendlyCompassHeading] - DIRECTIONS[B.humanFriendlyCompassHeading];
}

以下是我希望如何对数据进行排序的示例输出:

• (514m，北)诺丁汉特伦特大学艺术与设计学院

• (695m，北)诺丁汉植物园

• (424m，东北)阿奇亚姆中心

• (497m，东北)莎士比亚街卫斯理改革教堂

• (795m，东北)诺丁汉市区

• (796m，东北)诺丁汉维多利亚巴士站

• (438m，东)诺丁汉 session 中心

这是原始数组的一部分。稍后，我将使用数组中返回的 lat 和 lng 值添加从我的起始位置开始的方位、距离和人类友好值:

         "summary":"The Diocese of Nottingham, England, is a Roman Catholic diocese of the Latin Rite which covers an area of 13,074 km², taking in the counties of Nottinghamshire (excluding the district of Bassetlaw), Leicestershire, Derbyshire, Rutland and Lincolnshire (...)",
     "elevation":65,
     "lng":-1.1572,
     "distance":"0.0685",
     "countryCode":"GB",
     "rank":84,
     "lang":"en",
     "title":"Roman Catholic Diocese of Nottingham",
     "lat":52.9545,
     "wikipediaUrl":"en.wikipedia.org/wiki/Roman_Catholic_Diocese_of_Nottingham"
  },
  {  
     "summary":"The Cathedral Church of St. Barnabas in the city of Nottingham, England, is a cathedral of the Roman Catholic church. It is the mother church of the Diocese of Nottingham and seat of the Bishop of Nottingham. (...)",
     "elevation":67,
     "feature":"landmark",
     "lng":-1.15708,
     "distance":"0.0703",
     "countryCode":"GB",
     "rank":82,
     "lang":"en",
     "title":"Nottingham Cathedral",
     "lat":52.95466,
     "wikipediaUrl":"en.wikipedia.org/wiki/Nottingham_Cathedral"
  },
  {  
     "summary":"The Albert Hall, Nottingham, is a City Centre Conference and Concert venue, situated in Nottingham, England. (...)",
     "elevation":61,
     "feature":"landmark",
     "lng":-1.1563944444444442,
     "distance":"0.1217",
     "countryCode":"GB",
     "rank":72,
     "lang":"en",
     "title":"Albert Hall, Nottingham",
     "lat":52.95441944444445,
     "wikipediaUrl":"en.wikipedia.org/wiki/Albert_Hall%2C_Nottingham"
  },
  {  
     "summary":"The Nottingham Playhouse is a theatre in Nottingham, Nottinghamshire, England. It was first established as a repertory theatre in the 1950s when it operated from a former cinema. Directors during this period included Val May and Frank Dunlop (...)",
     "elevation":67,
     "feature":"landmark",
     "lng":-1.1577,
     "distance":"0.1235",
     "countryCode":"GB",
     "rank":77,
     "lang":"en",
     "title":"Nottingham Playhouse",
     "lat":52.9537,
     "wikipediaUrl":"         en.wikipedia.org/wiki/Nottingham_Playhouseenter code here

Answer 1

编写与 Array.prototype.sort 一起使用的比较函数，您可以使用如下函数:

function composeComparisons(cmpFunctions) {
     return function (a, b) {
          for (var i = 0, result; i < cmpFunctions.length; i++) {
                result = cmpFunctions[i](a, b);
                if (result) {
                    return result;
                }
          }
          return 0;
     }
};

它将返回一个函数，该函数将项目与每个比较函数进行比较，直到获得显着的结果。

你会这样使用它:

// From most significant to least significant comparison function
var myCmp = composeComparisons([cmpByBearing, cmpByDistance, cmpByFriendliness]);

array.sort(myCmp);

提醒一下，如果 a 大于 b，则比较函数 cmp(a, b) 返回正数，如果 a 大于 b，则返回负数如果 b 大于 a，则为数字；如果项目相同，则为 0。