通过数组中每个JSON对象中的值从JSON数组中删除重复项

Question

如果在一个数组中有两个JSON对象，对于特定的字段具有相同的值，那么我想将它们标记为重复 。 我要删除其中之一。 同样，当有多个重复项时，我只想保留最后一个对象（最新）。

names_array = [
    {name: "a",  age: 15},
    {name: "a",  age: 16},
    {name: "a",  age: 17},
    {name: "b",  age: 18}
    {name: "b",  age: 19}];

我希望输出是

names_array_new = 
    {name: "a",  age: 17},
    {name: "b",  age: 19}];

我已经进行了搜索，但是只发现了在整个对象相同时如何删除重复项。

Answer 1

应该这样做：

names_array = [
    {name: "a",  age: 15},
    {name: "a",  age: 16},
    {name: "a",  age: 17},
    {name: "b",  age: 18},
    {name: "b",  age: 19}];

function hash(o){
    return o.name;
}    

var hashesFound = {};

names_array.forEach(function(o){
    hashesFound[hash(o)] = o;
})

var results = Object.keys(hashesFound).map(function(k){
    return hashesFound[k];
})

hash函数决定哪些对象是重复的， hashesFound对象将每个哈希值与产生该哈希值的最新对象存储在一起， results数组包含匹配的对象。

Answer 2

稍微不同的方法：

 var names_array = [ { name: "a", age: 15 }, { name: "a", age: 16 }, { name: "a", age: 17 }, { name: "b", age: 18 }, { name: "b", age: 19 } ]; var names_array_new = names_array.reduceRight(function (r, a) { r.some(function (b) { return a.name === b.name; }) || r.push(a); return r; }, []); document.getElementById('out').innerHTML = JSON.stringify(names_array_new, 0, 4); 

 <pre id="out"></pre> 

Answer 3

var names_array = [
{name: "a", age: 15},
{name: "a", age: 16},
{name: "a", age: 17},
{name: "b", age: 18},
{name: "b", age: 19}];

function removeDuplicate(arr, prop) {
var new_arr = [];
var lookup = {};
for (var i in arr) {
    lookup[arr[i][prop]] = arr[i];
}
for (i in lookup) {
    new_arr.push(lookup[i]);
}
return new_arr;}
var newArray = removeDuplicate(names_array, 'name');
console.log("Result "+newArray);

Answer 4

Array.from（new Set（brand.map（obj => JSON.stringify（obj））））。map（item => JSON.parse（item））