Javascript从数组中删除重复的对象

Question

i'm having trouble to remove duplicated object from my array

example:

var list = [{place:"AAA",name:"Me"}, {place:"BBB",name:"You"}, {place:"AAA",name:"Him"}];

in this example i have 3 objects, and i want to remove the object that have the duplicated place

Answer 1

Just in case someone wonders: underscore.js solution:

var list = [{place:"AAA",name:"Me"}, {place:"BBB",name:"You"}, {place:"AAA",name:"Him"}];

_.uniq(list, function(item, key, a) { 
    return item.place;
})

Example Fiddle

Answer 2

A simple one:

 var list = [{place:"AAA",name:"Me"}, {place:"BBB",name:"You"}, {place:"AAA",name:"Him"}]; list.forEach(function(i) { var duplicates = list.filter(function(j) { return j !== i && j.place == i.place; }); duplicates.forEach(function(d) { list.splice(list.indexOf(d), 1); }); }); // list = [{place:"AAA",name:"Me"}, {place:"BBB",name:"You"}]; document.write(JSON.stringify(list));

Answer 3

Try this.

var result = {};
for (i = 0, n = arr.length; i < n; i++) {
    var item = arr[i];
    result[ item.place + " - " + item.name ] = item;
}

Loop the result again, and recreate the array.

i = 0;    
for(var item in result) {
    clearnArr[i++] = result[item];
}

Answer 4

Create a object to store the items by their place value, as the new item with the same key will overwrite the old one, this will easily remove all dulplicates.

 var list = [{place:"AAA",name:"Me"}, {place:"BBB",name:"You"}, {place:"AAA",name:"Him"}]; var removeDuplicate = function(list) { var keyStore = {}; var output = []; // If you want to creata totally new one from old, use // list = JSON.parse(JSON.stringify(list)); // The above commented out code will create a copy of list, so the items in output will not affect the original ones. list.forEach(function(item) { // new one overwrites old one. keyStore[item.place] = item; }); var key; for (key in keyStore) { output.push(keyStore[key]); } return output; }; console.log(removeDuplicate(list));

Answer 5

As you added:

i want to remove just one, dont matter wich one

If you want to remove duplicated items and keep only the first occcurence of particular place , you can simply use a simple loop to re-create a new array from the input:

var list = [{place:"AAA",name:"Me"}, {place:"BBB",name:"You"}, {place:"AAA",name:"Him"}];

var uniqPlace = function(array){
    var result = [];
    array.forEach(function(el){
        if (result.filter(function(n){ return n.place === el.place }).length==0){
            result.push(el);
        }
    })
    return result;
}

Output:

uniqPlace(list);

[{"place":"AAA","name":"Me"},{"place":"BBB","name":"You"}]

Answer 6

3 way to remove duplicate objects from array

 let list = [{place:"AAA",name:"Me"}, {place:"BBB",name:"You"}, {place:"AAA",name:"Him"}]; let output1 = Array.from(new Set(list.map(list=>list.place))).map(place=>{ return { place: place, name: list.find(a=>a.place===place).name } }) console.log('------------------------1st way') console.log(output1) let output2 = list.reduce((accumulator, element) => { if (!accumulator.find(el => el['place'] === element['place'])) { accumulator.push(element); } return accumulator; },[]); console.log('------------------------2nd way') console.log(output2) const output3 = []; const map = new Map(); for (const object of list) { if(!map.has(object.place)){ map.set(object.place, true); output3.push({ place: object.place, name: object.name }); } } console.log('------------------------3rd way') console.log(output3)