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从数组中删除基于多个键的重复对象

javascriptfilteruniquereducearray-of-dict
45
假设给定以下对象数组：

Assuming an array of objects as follows:

const listOfTags = [
    {id: 1, label: "Hello", color: "red", sorting: 0},
    {id: 2, label: "World", color: "green", sorting: 1},
    {id: 3, label: "Hello", color: "blue", sorting: 4},
    {id: 4, label: "Sunshine", color: "yellow", sorting: 5},
    {id: 5, label: "Hello", color: "red", sorting: 6},
]

如果标签和颜色相同，就会出现重复条目。在这种情况下，id = 1和id = 5的对象是重复的。

我该如何筛选这个数组并删除重复项？

我知道一些解决方案，比如使用以下方法对一个键进行过滤：

const unique = [... new Set(listOfTags.map(tag => tag.label)]

但是多个键怎么办呢？

根据评论的要求，这里是所需的结果:

[
    {id: 1, label: "Hello", color: "red", sorting: 0},
    {id: 2, label: "World", color: "green", sorting: 1},
    {id: 3, label: "Hello", color: "blue", sorting: 4},
    {id: 4, label: "Sunshine", color: "yellow", sorting: 5},
]
14个回答
1
const listOfTags = [
    {id: 1, label: "Hello", color: "red", sorting: 0},
    {id: 2, label: "World", color: "green", sorting: 1},
    {id: 3, label: "Hello", color: "blue", sorting: 4},
    {id: 4, label: "Sunshine", color: "yellow", sorting: 5},
    {id: 5, label: "Hello", color: "red", sorting: 6},
];

let keysList = Object.keys(listOfTags[0]); // Get First index Keys else please add your desired array

let unq_List = [];

keysList.map(keyEle=>{
  if(unq_List.length===0){
      unq_List = [...unqFun(listOfTags,keyEle)];
  }else{
      unq_List = [...unqFun(unq_List,keyEle)];
  }
});

function unqFun(array,key){
    return [...new Map(array.map(o=>[o[key],o])).values()]
}

console.log(unq_List);
0

或许有帮助。从数组中提取重复项，然后删除所有重复项。

// Initial database data
[
    { key: "search", en:"Search" },
    { key: "search", en:"" },
    { key: "alert", en:"Alert" },
    { key: "alert", en:"" },
    { key: "alert", en:"" }
]


// Function called
async function removeDuplicateItems() {
    try {
        // get data from database
        const { data } = (await getList());
        
        // array reduce method for obj.key
        const reduceMethod = data.reduce((x, y) => {
            x[y.key] = ++x[y.key] || 0;
            return x;
        }, {});

        // find duplicate items by key and checked whether "en" attribute also has value
        const duplicateItems = data.filter(obj => !obj.en && reduceMethod[obj.key]);
        console.log('duplicateItems', duplicateItems);

        // remove all dublicate items by id
        duplicateItems.forEach(async (obj) => {
            const deleteResponse = (await deleteItem(obj.id)).data;
            console.log('Deleted item: ', deleteResponse);
        });

    } catch (error) {
        console.log('error', error);
    }
}


// Now database data: 
[
    { key: "search", en:"Search" },
    { key: "alert", en:"Alert" }
]
0

一个解决方案是迭代数组并使用一个Map来存储到目前为止已经遇到的键-值对。

通过这种方式查找重复项应该相当快（与嵌套循环或.filter + .find方法相比）。

此外，这些值可以是任何原始类型；它们不会被字符串化或连接以进行比较（这可能会导致不正确的比较）。

const listOfTags = [
    {id: 1, label: "Hello",    color: "red",    sorting: 0},
    {id: 2, label: "World",    color: "green",  sorting: 1},
    {id: 3, label: "Hello",    color: "blue",   sorting: 4},
    {id: 4, label: "Sunshine", color: "yellow", sorting: 5},
    {id: 5, label: "Hello",    color: "red",    sorting: 6}
];

let map = new Map();
let result = [];
listOfTags.forEach(function(obj) {
    if (map.has(obj.label) === false) {
        map.set(obj.label, new Map());
    }
    if (map.get(obj.label).has(obj.color) === false) {
        map.get(obj.label).set(obj.color, true);
        result.push(obj)
    }
});
console.log(result);

0
const listOfTags = [
    {id: 1, label: "Hello", color: "red", sorting: 0},
    {id: 2, label: "World", color: "green", sorting: 1},
    {id: 3, label: "Hello", color: "blue", sorting: 4},
    {id: 4, label: "Sunshine", color: "yellow", sorting: 5},
    {id: 5, label: "Hello", color: "red", sorting: 6},
]

const removeDuplicate = listOfTags.reduce((prev, item) => {
  const label = item.label;
  const color = item.color;
  const tempPrev = prev;
  if (tempPrev.length) {
    const isExistInPrevArray = tempPrev.some((i) => i.label ===  label && i.color === color);
    if (isExistInPrevArray == false) {
      return [...tempPrev, ...[item]];
    } else {
      return [...tempPrev, ...[]];
    }
  } else {
    return [...tempPrev, ...[item]];
  }
}, []);

console.log('removeDuplicate',removeDuplicate)

输出

removeDuplicate [
  { id: 1, label: 'Hello', color: 'red', sorting: 0 },
  { id: 2, label: 'World', color: 'green', sorting: 1 },
  { id: 3, label: 'Hello', color: 'blue', sorting: 4 },
  { id: 4, label: 'Sunshine', color: 'yellow', sorting: 5 }
]
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