通过数组

Question

如果某个数组中有两个JSON对象具有相同的特定字段值，那么我想将它们标记为重复。我想删除其中一个。同样，当有多个重复时，我只想保留最后一个对象（最新）。如果这是输入：

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

我希望输出为

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

我搜索了这个，但只发现了当整个对象相同时如何删除重复项。

Answer 1

这应该这样做：

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对象将每个散列值与生成该散列的最新对象一起存储，results数组包含匹配的对象。

Answer 2

略有不同的方法：

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（新Set（brand.map（obj => JSON.stringify（obj））））。map（item => JSON.parse（item））