比较数组对象并显示差异

Question

我有两个数组，我想比较它们并检查其中一个数组中是否有已删除的项目。如果有告诉我不同之处（已删除的项目）

下面是我想如何实现的代码：

 var completedList = [{id:1},{id:2},{id:3},{id:4},{id:7},{id:8}];
    var invalidList = [{id:3},{id:4},{id:5},{id:6}];

    // filter the items from the invalid list, out of the complete list
    var validList = completedList.map((item) => {
        console.log(item.id)
        return item.id;
        //console.log(invalidList.id);
    }).filter(item => {
        Object.keys(invalidList).map(key => {
            console.log(invalidList[key].id)
            //return !invalidList[key].id.includes(item.id);
        });
    })

    console.log(validList); // Print [1,2,7,8]

    // get a Set of the distinct, valid items
    var validItems = new Set(validList);

但是这个 returns 我很多 id's 我怎样才能通过数组映射并过滤对象属性 id？并且只显示这些数组对象的区别。

所以基本上我希望看到这些数组之间的差异，所以在这个例子中记录 id 的差异：1,2,5,6,7,8

Answer 1

我经常依赖 lodash 实现来进行比较。在 lo dash 中，您可以按照以下方式完成工作

_.intersectionWith(arr1, arr2, _.isEqual) - 为了相似性 _.differenceWith(arr1, arr2, _.isEqual) - 差异

这个答案仅限于使用 util 库来完成工作。如果您正在寻找确切的算法，我肯定会花一些时间来开发它并作为评论对此 post 进行回复。

谢谢

Answer 2

你可以拿一个 Set 来获得不同。为了获得彼此的差异（对称差异），您需要获得两个差异。

const
    difference = (a, b) => Array.from(b.reduce((s, v) => (s.delete(v), s), new Set(a))),
    getId = ({ id }) => id;

var completedList = [{ id: 1 }, { id: 2 }, { id: 3 }, { id: 4 }, { id: 7 }, { id: 8 }],
    invalidList = [{ id: 3 }, { id: 4 }, { id: 5 }, { id: 6 }],
    complete = completedList.map(getId),
    invalid = invalidList.map(getId),
    left = difference(complete, invalid),
    right = difference(invalid, complete),
    result = [...left, ...right]

console.log(result.join(' '));
console.log(left.join(' '));
console.log(right.join(' '));

Answer 3

这应该可以解决问题。

let completedList = [{id:1},{id:2},{id:3},{id:4},{id:7},{id:8}];
let invalidList = [{id:3},{id:4},{id:5},{id:6}];
// filter the items from the invalid list, out of the complete list
let temp1 = completedList.map(e => e.id);
let temp2 = invalidList.map(e => e.id);
let validList = temp1.filter(e => temp2.indexOf(e) === -1);
// find items only in invalidList
let difference = temp2.filter(e => temp1.indexOf(e) === -1);
console.log(validList); // Print [1,2,7,8]
console.log(difference);

Answer 4

var completedList = [{ id: 1 }, { id: 2 }, { id: 3 }, { id: 4 }, { id: 7 }, { id: 8 }];
var invalidList = [{ id: 3 }, { id: 4 }, { id: 5 }, { id: 6 }];

//get the items that are in the invalid list but not completed list
var filteredList1 = invalidList.filter((invalidListItem) => !completedList.find((item) => item.id === invalidListItem.id));

//get the items that are in  the completed list but not in the invalid list
var filteredList2 = completedList.filter((completedListItem) => !invalidList.find((item) => item.id === completedListItem.id));

//join the two arrays
var difference = filteredList1.concat(filteredList2);

//display the merged array and sort
console.log(difference.sort((item1, item2) => { return item1.id > item2.id ? 1 : item1.id < item2.id ? -1 : 0; }));

//outputs 1,2,5,6,7,8

比较数组对象并显示差异

Compare array objects and show difference

javascript

ecmascript-5

ecmascript-6