Javascript 只推送数组中的唯一元素
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push only unique elements in an array
提问by smtp
I have array object(x) that stores json (key,value) objects. I need to make sure that x only takes json object with unique key. Below, example 'id' is the key, so i don't want to store other json objects with 'item1' key.
我有存储 json (key,value) 对象的数组 object(x)。我需要确保 x 只接受具有唯一键的 json 对象。下面，示例 'id' 是键，所以我不想用 'item1' 键存储其他 json 对象。
x = [{"id":"item1","val":"Items"},{"id":"item1","val":"Items"},{"id":"item1","val":"Items"}]
var clickId = // could be "item1", "item2"....
var found = $.inArray(clickId, x); //
if(found >=0)
{
x.splice(found,1);
}
else{
x.push(new Item(clickId, obj)); //push json object
}
回答by stackoverfloweth
would this accomplish what you're looking for? https://jsfiddle.net/gukv9arj/3/
这会完成你正在寻找的吗？https://jsfiddle.net/gukv9arj/3/
x = [
{"id":"item1","val":"Items"},
{"id":"item1","val":"Items"},
{"id":"item2","val":"Items"}
];
var clickId = [];
var list = JSON.parse(x);
$.each(list, function(index, value){
if(clickId.indexOf(value.id) === -1){
clickId.push(value.id);
}
});
回答by Dave
You can't use inArray()because you are searching for an object.
您无法使用，inArray()因为您正在搜索object.
I'd recommend rewriting a custom find using Array.some()as follows.
我建议使用Array.some()如下方式重写自定义查找。
var x = [{"id":"item1","val":"Items"},{"id":"item1","val":"Items"},{"id":"item1","val":"Items"}]
var clickId = "item1";
var found = x.some(function(value) {
return value.id === clickId;
});
alert(found);回答by Populus
This is how I would do it in pure javascript.
这就是我在纯 javascript 中的做法。
var x = [{"id":"item1","val":"Items"},{"id":"item1","val":"Items"},{"id":"item1","val":"Items"}];
function unique(arr, comparator) {
var uniqueArr = [];
for (var i in arr) {
var found = false;
for (var j in uniqueArr) {
if (comparator instanceof Function) {
if (comparator.call(null, arr[i], uniqueArr[j])) {
found = true;
break;
}
} else {
if (arr[i] == uniqueArr[j]) {
found = true;
break;
}
}
}
if (!found) {
uniqueArr.push(arr[i]);
}
}
return uniqueArr;
};
u = unique(x, function(a,b){ return a.id == b.id; });
console.log(u);
y = [ 1,1,2,3,4,5,5,6,1];
console.log(unique(y));回答by Ron Sims II
JS objects are great tools to use for tracking unique items. If you start with an empty object, you can incrementally add keys/values. If the object already has a key for a given item, you can set it to some known value that is use used to indicate a non-unique item.
JS 对象是用于跟踪独特项目的绝佳工具。如果您从一个空对象开始，您可以逐步添加键/值。如果对象已经具有给定项目的键，您可以将其设置为某个已知值，用于指示非唯一项目。
You could then loop over the object and push the unique items to an array.
然后，您可以遍历对象并将唯一项推送到数组。
var itemsObj = {};
var itemsList = [];
x = [{"id":"item1","val":"foo"},
{"id":"item2","val":"bar"},
{"id":"item1","val":"baz"},
{"id":"item1","val":"bez"}];
for (var i = 0; i < x.length; i++) {
var item = x[i];
if (itemsObj[item.id]) {
itemsObj[item.id] = "dupe";
}
else {
itemsObj[item.id] = item;
}
}
for (var myKey in itemsObj) {
if (itemsObj[myKey] !== "dupe") {
itemsList.push(itemsObj[myKey]);
}
}
console.log(itemsList);
See a working example here: https://jsbin.com/qucuso
在此处查看工作示例：https: //jsbin.com/qucuso
If you want a list of items that contain only the first instance of an id, you can do this:
如果你想要一个只包含一个 id 的第一个实例的项目列表，你可以这样做：
var itemsObj = {};
var itemsList = [];
x = [{"id":"item1","val":"foo"},
{"id":"item2","val":"bar"},
{"id":"item1","val":"baz"},
{"id":"item1","val":"bez"}];
for (var i = 0; i < x.length; i++) {
var item = x[i];
if (!itemsObj[item.id]) {
itemsObj[item.id] = item;
itemsList.push(item);
}
}
console.log(itemsList);
回答by TheCleverIdiot
This is late but I did something like the following:
这很晚了，但我做了如下的事情：
let MyArray = [];
MyArray._PushAndRejectDuplicate = function(el) {
if (this.indexOf(el) == -1) this.push(el)
else return;
}
MyArray._PushAndRejectDuplicate(1); // [1]
MyArray._PushAndRejectDuplicate(2); // [1,2]
MyArray._PushAndRejectDuplicate(1); // [1,2]
回答by BruceJo
Create a very readable solution with lodash.
使用 lodash 创建一个非常易读的解决方案。
x = _.unionBy(x, [new Item(clickId, obj)], 'id');
x = _.unionBy(x, [new Item(clickId, obj)], 'id');
