JS数组对象去重(4种方法)

问题:数组对象去重

var arr = [{name: ‘a’,id: 1}, {name: ‘a’,id: 2}, {name: ‘b’,id: 3}, {name: ‘c’,id: 4}, {name: ‘c’,id: 6}, {name: ‘b’,id: 6}, {name: ‘d’,id: 7}];
对数组对象name进行去重处理, 结果显示为:
[{name: ‘a’,id: 1}, {name: ‘b’,id: 3}, {name: ‘c’,id: 4}, {name: ‘d’,id: 7}];

方法一:es5冒泡排序法,去重arr
var arr = [{name: 'a',id: 1}, {name: 'a',id: 2}, {name: 'b',id: 3}, {name: 'c',id: 4},
 {name: 'c',id: 6}, {name: 'b',id: 6}, {name: 'd',id: 7}];
function deWeight() {
    for (var i = 0; i < arr.length - 1; i++) {
        for (var j = i + 1; j < arr.length; j++) {
            if (arr[i].name == arr[j].name) {
                arr.splice(j, 1);
                //因为数组长度减小1,所以直接 j++ 会漏掉一个元素,所以要 j--
                j--;
            }
        }
    }
    return arr;
}
var newArr = deWeight();
console.log('%c%s', 'color:red;', '方法一:es5,newArr', newArr);
方法二:es5新建数据双重循环,去重arr2
var arr2 = [{name: 'a',id: 1}, {name: 'a',id: 2}, {name: 'b',id: 3}, {name: 'c',id: 4},
 {name: 'c',id: 6}, {name: 'b',id: 6}, {name: 'd',id: 7}];
var temp = [];
function deWeightTwo() {
    arr2.forEach(function(a) {
        var check = temp.every(function(b) {
            return a.name !== b.name;
        })
        check ? temp.push(a) : ''
    })
    return temp;
}
var newArr2 = deWeightTwo();
console.log('%c%s', 'color:red;', '方法二:es5,newArr2', newArr2);
方法三:es6的Map(),去重arr3
var arr3 = [{name: 'a',id: 1}, {name: 'a',id: 2}, {name: 'b',id: 3}, {name: 'c',id: 4},
 {name: 'c',id: 6}, {name: 'b',id: 6}, {name: 'd',id: 7}];
let deWeightThree = () => {
    let map = new Map();
    for (let item of arr3) {
        if (!map.has(item.name)) {
            map.set(item.name, item);
        }
    }
    return [...map.values()];
}
let newArr3 = deWeightThree();
console.log('%c%s', 'color:red;', '方法三:es6,newArr3', newArr3);
方法四:es5,对象法去重arr4
var arr4 = [{name: 'a',id: 1}, {name: 'a',id: 2}, {name: 'b',id: 3}, {name: 'c',id: 4},
 {name: 'c',id: 6}, {name: 'b',id: 6}, {name: 'd',id: 7}];
// array.reduce(function(total, currentValue, currentIndex, arr), initialValue)
// (function(必选初始值或计算结束返回值, 必选当前元素, 可选索引, 可选原数组),可选函数初始值)
var obj = {};
function deWeightFour() {
    arr4 = arr4.reduce(function(a, b) {
        obj[b.name] ? '' : obj[b.name] = true && a.push(b);
        return a;
    }, [])
    return arr4;
}
var newArr4 = deWeightFour();
console.log('%c%s', 'color:red;', '方法四:es5,newArr4', newArr4);

原文作者:匆匆那年_海,原文地址:https://www.jianshu.com/p/7c12cbaa817b

给TA买糖
共{{data.count}}人
人已赞赏
JavaScript

手写一个原生JS弹窗消息提醒插件

2020-10-27 23:52:02

JavaScript

HTML + JS 实现图片下载功能

2020-12-7 13:11:22

0 条回复 A文章作者 M管理员
    暂无讨论,说说你的看法吧
个人中心
购物车
优惠劵
今日签到
有新私信 私信列表
搜索