我有一个JavaScript对象数组:

var objs = [ 
    { first_nom: 'Lazslo', last_nom: 'Jamf'     },
    { first_nom: 'Pig',    last_nom: 'Bodine'   },
    { first_nom: 'Pirate', last_nom: 'Prentice' }
];

如何在JavaScript中按last_nom的值对它们进行排序?

我知道排序(a,b),但这似乎只适用于字符串和数字。是否需要向对象添加toString()方法?


当前回答

let propName = 'last_nom';

let sorted_obj = objs.sort((a,b) => {
    if(a[propName] > b[propName]) {
        return 1;
    }
    if (a[propName] < b[propName]) {
        return -1;
    }
    return 0;
}

//This works because the js built-in sort function allows us to define our
//own way of sorting, this funny looking function is simply telling `sort` how to
//determine what is larger. 
//We can use `if(a[propName] > b[propName])` because string comparison is already built into JS
//if you try console.log('a' > 'z' ? 'a' : 'z')
//the output will be 'z' as 'a' is not greater than 'z'
//The return values 0,-1,1 are how we tell JS what to sort on. We're sorting on the last_nom property of the object. 
//When sorting a list it comes down to comparing two items and how to determine which one of them is "larger". 
//We need a way to tell JS how to determine which one is larger. 
//The sort defining function will use the case that returns a 1 to mean that a > b
//and the case that returns -1 to mean that a < b

其他回答

使用xPrototype的sortBy:

var o = [
  { Name: 'Lazslo', LastName: 'Jamf'     },
  { Name: 'Pig',    LastName: 'Bodine'   },
  { Name: 'Pirate', LastName: 'Prentice' },
  { Name: 'Pag',    LastName: 'Bodine'   }
];


// Original
o.each(function (a, b) { console.log(a, b); });
/*
 0 Object {Name: "Lazslo", LastName: "Jamf"}
 1 Object {Name: "Pig", LastName: "Bodine"}
 2 Object {Name: "Pirate", LastName: "Prentice"}
 3 Object {Name: "Pag", LastName: "Bodine"}
*/


// Sort By LastName ASC, Name ASC
o.sortBy('LastName', 'Name').each(function(a, b) { console.log(a, b); });
/*
 0 Object {Name: "Pag", LastName: "Bodine"}
 1 Object {Name: "Pig", LastName: "Bodine"}
 2 Object {Name: "Lazslo", LastName: "Jamf"}
 3 Object {Name: "Pirate", LastName: "Prentice"}
*/


// Sort by LastName ASC and Name ASC
o.sortBy('LastName'.asc, 'Name'.asc).each(function(a, b) { console.log(a, b); });
/*
 0 Object {Name: "Pag", LastName: "Bodine"}
 1 Object {Name: "Pig", LastName: "Bodine"}
 2 Object {Name: "Lazslo", LastName: "Jamf"}
 3 Object {Name: "Pirate", LastName: "Prentice"}
*/


// Sort by LastName DESC and Name DESC
o.sortBy('LastName'.desc, 'Name'.desc).each(function(a, b) { console.log(a, b); });
/*
 0 Object {Name: "Pirate", LastName: "Prentice"}
 1 Object {Name: "Lazslo", LastName: "Jamf"}
 2 Object {Name: "Pig", LastName: "Bodine"}
 3 Object {Name: "Pag", LastName: "Bodine"}
*/


// Sort by LastName DESC and Name ASC
o.sortBy('LastName'.desc, 'Name'.asc).each(function(a, b) { console.log(a, b); });
/*
 0 Object {Name: "Pirate", LastName: "Prentice"}
 1 Object {Name: "Lazslo", LastName: "Jamf"}
 2 Object {Name: "Pag", LastName: "Bodine"}
 3 Object {Name: "Pig", LastName: "Bodine"}
*/

我将给您一个实现选择排序算法的解决方案。它简单有效。

var objs = [
  { first_nom: 'Lazslo', last_nom: 'Jamf'     },
  { first_nom: 'Pig',    last_nom: 'Bodine'   },
  { first_nom: 'Pirate', last_nom: 'Prentice' }
];


function selection_Sort(num) {
  //console.log(num);
  var temp, index;
  for (var i = 0; i <= num.length - 1; i++) {
    index = i;

    for (var j = i + 1; j <= num.length - 1; j++) {
      // You can use first_nom/last_nom, any way you choose to sort

      if (num[j].last_nom < num[index].last_nom) {
        index = j;
      }
    }

    // Below is the swapping part
    temp = num[i].last_nom;
    num[i].last_nom = num[index].last_nom;
    num[index].last_nom = temp;
  };
  console.log(num);
  return num;
}

selection_Sort(objs);

Deep

基于这篇优秀的教程,我想开发Vlad Bezden的答案,并解释为什么localeCompare优于标准比较方法,如strA>strB。让我们运行以下示例:

console.log(“Österreich”>“Zealand”);//我们期望错误console.log(“a”>“Z”);//我们期望错误

原因是在JavaScript中,所有字符串都使用UTF-16编码

让str=“”;//JavaScript中的字符顺序for(设i=65;i<=220;i++){str+=字符串.fromCodePoint(i);//代码到字符}console.log(str);

首先是大写字母(有小代码),然后是小写字母,然后是字符Ö(在z之后)。这就是为什么我们在第一个代码段中得到正确的原因,因为运算符>比较字符代码。

如您所见,比较不同语言中的字符是一项非常重要的任务,但幸运的是,现代浏览器支持国际化标准ECMA-402。所以在JavaScript中,我们有strA.localeCompare(strB)来完成任务(-1表示strA小于strB;1表示相反;0表示相等)

console.log('Österreich'.localeCompare('Zealand'));//我们期望-1console.log('a'.localeCompare('Z'));//我们期望-1

我想补充一点,localeCompare支持两个参数:语言和其他规则:

var对象=[{first_nom:'Lazslo',last_nom:'Jamf'},{first_nom:'猪',last_nom:'Bodine'},{first_nom:'海盗',last_nom:'Prentice'},{first_nom:'测试',last_nom:'jamf'}];objs.sort((a,b)=>a.last_nom.localeCompare(b.last_nom,'en',{sensitity:'case'}))console.log(objs);//在'>'比较中,'Jamf'不会在'Jamf'旁边

如果您有嵌套对象

const objs = [{
        first_nom: 'Lazslo',
        last_nom: 'Jamf',
        moreDetails: {
            age: 20
        }
    }, {
        first_nom: 'Pig',
        last_nom: 'Bodine',
        moreDetails: {
            age: 21
        }
    }, {
        first_nom: 'Pirate',
        last_nom: 'Prentice',
        moreDetails: {
            age: 22
        }
    }];

nestedSort = (prop1, prop2 = null, direction = 'asc') => (e1, e2) => {
        const a = prop2 ? e1[prop1][prop2] : e1[prop1],
            b = prop2 ? e2[prop1][prop2] : e2[prop1],
            sortOrder = direction === "asc" ? 1 : -1
        return (a < b) ? -sortOrder : (a > b) ? sortOrder : 0;
    }

并称之为

objs.sort(nestedSort("last_nom"));
objs.sort(nestedSort("last_nom", null, "desc"));
objs.sort(nestedSort("moreDetails", "age"));
objs.sort(nestedSort("moreDetails", "age", "desc"));

对对象数组进行排序

// Data
var booksArray = [
    { first_nom: 'Lazslo', last_nom: 'Jamf'     },
    { first_nom: 'Pig',    last_nom: 'Bodine'   },
    { first_nom: 'Pirate', last_nom: 'Prentice' }
];

// Property to sort by
var args = "last_nom";

// Function to sort the data by the given property
function sortByProperty(property) {
    return function (a, b) {
        var sortStatus = 0,
            aProp = a[property].toLowerCase(),
            bProp = b[property].toLowerCase();
        if (aProp < bProp) {
            sortStatus = -1;
        } else if (aProp > bProp) {
            sortStatus = 1;
        }
        return sortStatus;
    };
}

// Implementation
var sortedArray = booksArray.sort(sortByProperty(args));

console.log("sortedArray: " + JSON.stringify(sortedArray) );

控制台日志输出:

"sortedArray: 
[{"first_nom":"Pig","last_nom":"Bodine"},
{"first_nom":"Lazslo","last_nom":"Jamf"},
{"first_nom":"Pirate","last_nom":"Prentice"}]"

基于此来源改编:代码段:如何按属性对JSON对象数组排序