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How to remove complete unique value from array [duplicate]

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How to remove all duplicates from an array of objects?
(77 answers)
Closed 3 years ago.
How to remove complete record of same object in array please help me this, I am using below funtion but its only remove one value I want remove complete object of same object
var data = [{
"QuestionOid": 1,
"name": "hello",
"label": "world"
}, {
"QuestionOid": 2,
"name": "abc",
"label": "xyz"
}, {
"QuestionOid": 1,
"name": "hello",
"label": "world"
}];
function removeDumplicateValue(myArray) {
var newArray = [];
$.each(myArray, function (key, value) {
var exists = false;
$.each(newArray, function (k, val2) {
if (value.QuestionOid == val2.QuestionOid) { exists = true };
});
if (exists == false && value.QuestionOid != undefined) { newArray.push(value); }
});
return newArray;
}
I want result like this
[{
"QuestionOid": 2,
"name": "abc",
"label": "xyz"
}]

You can use reduce.
var data = [{"QuestionOid": 1,"name": "hello","label": "world"}, {"QuestionOid": 2,"name": "abc","label": "xyz"}, {"QuestionOid": 1,"name": "hello","label": "world"}];
let op = data.reduce((op,inp)=>{
if(op[inp.QuestionOid]){
op[inp.QuestionOid].count++
} else {
op[inp.QuestionOid] = {...inp,count:1}
}
return op
},{})
let final = Object.values(op).reduce((op,{count,...rest})=>{
if(count === 1){
op.push(rest)
}
return op
},[])
console.log(final)

Do with Array#filter.Filter the array matching QuestionOid value equal to 1
var data = [{ "QuestionOid": 1, "name": "hello", "label": "world" }, { "QuestionOid": 2, "name": "abc", "label": "xyz" }, { "QuestionOid": 1, "name": "hello", "label": "world" }]
var res = data.filter((a, b, c) => c.map(i => i.QuestionOid).filter(i => i == a.QuestionOid).length == 1)
console.log(res)

check to see if all objects in an array has a common property

I have an array of objects which I am trying to loop over and check for a common key if it exists for all objects. if the specific key does not exist for all objects I return false.
Here is my code
var x = [{
"item": "alpha",
"value": "red"
}, {
"item": "beta",
"value": "blue"
}, {
"item": "beta",
"value": "gama"
}]
function test(obj) {
var count = 0;
var out = false;
for (var i = 0; i < obj.length; i++) {
if (obj[i].hasOwnProperty('value')) {
count = i;
}
}
if (count == obj.length) {
out = true
}
}
console.log(test(x))
I am getting undefined. Cant figure out what am I missing here

A really simple way to do this is to use Array#every like this
var x = [{
"item": "alpha",
"value": "red"
}, {
"item": "beta",
"value": "blue"
}, {
"item": "beta",
"value": "gama"
}]
function test(obj) {
return obj.every(a => a.hasOwnProperty("value"));
}
console.log(test(x))
Update
As rightfully mentioned by this comment first.

Here can be the simple solution for this object:
var x = [{
"item": "alpha",
"value": "red"
}, {
"item": "beta",
"value": "blue"
}, {
"item": "beta",
"value": "gama"
}];
function test(obj) {
var keyCount = 0;
obj.forEach(function (item, index) {
item.hasOwnProperty('value') && ++keyCount;
});
return keyCount == obj.length;
}
console.log(test(x));

Here is my implementation, which finds every matching key, even nested keys, given a set of objects:
function recurse_obj(obj, cb, _stack = []) {
for (var k in obj) {
cb(k, obj[k], _stack);
if (obj.hasOwnProperty(k) && (obj[k] instanceof Object)) {
_stack.push(k);
recurse_obj(obj[k], cb, _stack);
_stack.pop();
}
}
}
function obj_all_keys(obj) {
var tmp = [];
recurse_obj(obj, (k, v, stack) => {
var ext = (stack.length) ? "." : "";
tmp.push(stack.join(".").concat(ext, k));
});
return tmp;
}
function key_intersection(...objs) {
var lookup = {};
objs.forEach(o => {
obj_all_keys(o).forEach(k => {
if (k in lookup === false)
lookup[k] = 0;
lookup[k]++;
});
});
for (var k in lookup)
if (lookup[k] !== objs.length)
delete lookup[k];
return lookup;
}
Here is the calling code:
var me = { name: { first: "rafael", last: "cepeda" }, age: 23, meta: { nested: { foo: { bar: "hi" } } } };
console.log(key_intersection(me, { name: { first: "hi" } }));
Output: { name: 2, 'name.first': 2 }
The object returned includes only the keys that are found in all the objects, the set intersection, the counts are from book-keeping, and not removed in the callee for performance reasons, callers can do that if need be.
Keys that are included in other nested keys could be excluded from the list, because their inclusion is implied, but I left them there for thoroughness.
Passing a collection (array of objects) is trivial:
key_intersection.apply(this, collection);
or the es6 syntax:
key_intersection(...collection);

How to parse nested JSON in Javascript?

I am trying to parse and show JSON data (product catalog) using XMLHttpRequest method. I am able to display the brands and their names, but not able to showcase list of products progmatically.
Here is the sample JSON request:
{
"products": {
"laptop": [{
"brand": "sony",
"price": "$1000"
}, {
"brand": "acer",
"price": "$400"
}],
"cellphone": [{
"brand": "iphone",
"price": "$800"
}, {
"brand": "htc",
"price": "$500"
}],
"tablets": [{
"brand": "iPad",
"price": "$800"
}, {
"brand": "htc-tab",
"price": "$500"
}]
}
}
Right now I am using following code to show data in tabluar form:
function loadJSON() {
var data_file = "http://localhost/AJAX/productcatalog.json";
var http_request = new XMLHttpRequest();
http_request.onreadystatechange = function () {
if ((http_request.readyState == 4) && (http_request.status == 200)) {
// Javascript function JSON.parse to parse JSON data
var jsonObj = JSON.parse(http_request.responseText);
data = '<table border="2"><tr><td>Type</td><td>Brand</td><td>Price</td></tr>';
var i = 0;
debugger;
for (i = 0; i < jsonObj["products"].laptop.length; i++)
{
obj = jsonObj["products"].laptop[i];
data = data + '<tr><td>laptop</td><td>' + obj.brand + '</td><td>' + obj.price + '</td></tr>';
}
for (i = 0; i < jsonObj["products"].cellphone.length; i++)
{
obj = jsonObj["products"].cellphone[i];
data = data + '<tr><td>laptop</td><td>' + obj.brand + '</td><td>' + obj.price + '</td></tr>';
}
for (i = 0; i < jsonObj["products"].tablets.length; i++)
{
obj = jsonObj["products"].tablets[i];
data = data + '<tr><td>laptop</td><td>' + obj.brand + '</td><td>' + obj.price + '</td></tr>';
}
data += '</table>';
document.getElementById("demo").innerHTML = data;
}
}
http_request.open("GET", data_file, true);
http_request.send();
}
Question What is the way to fetch product list , i.e. products, cellphone and tablets ? Right now I have hardcoded that in order to fetch complete list of brands. Please advice. (I want to use plain javascript and not jquery)
Thanks!

It sounds like what you're missing is the "How do I iterate over an object when I don't know all the keys".
An object is a set of key, value pairs. You can use for/in syntax: for( var <key> in <object> ){} to get each key.
For your use case it might be something like:
var products = jsonObject['products'];
for( var productName in products ){
//productName would be "laptop", "cellphone", etc.
//products[productName] would be an array of brand/price objects
var product = products[productName];
for( var i=0; i<product.length; i++ ){
//product[i].brand
//product[i].price
}
}
In practice, I might use something a little less verbose, but this makes it easier to understand what is going on.

To achieve the expected i have used for loop and HTML DOM createElement() Method
var product_catalog = {
"products": {
"laptop": [{
"brand": "sony",
"price": "$1000"
}, {
"brand": "acer",
"price": "$400"
}],
"cellphone": [{
"brand": "iphone",
"price": "$800"
}, {
"brand": "htc",
"price": "$500"
}],
"tablets": [{
"brand": "iPad",
"price": "$800"
}, {
"brand": "htc-tab",
"price": "$500"
}]
}
};
var output = document.querySelector('#product tbody');
function build(JSONObject) {
/**get all keys***/
var keys = Object.keys(JSONObject);
/**get all subkeys***/
var subkeys = Object.keys(JSONObject[keys]);
console.log(subkeys);
/**loop sub keys to build HTML***/
for (var i = 0, tr, td; i < subkeys.length; i++) {
tr = document.createElement('tr');
td = document.createElement('td');
td.appendChild(document.createTextNode(subkeys[i]));
tr.appendChild(td);
output.appendChild(tr);
}
};
build(product_catalog);
HTML:
Coepen URL for reference- http://codepen.io/nagasai/pen/xOOqMv
Hope this works for you :)

Look at this example:
var x = data.key1.children.key4;
var path = "data";
function search(path, obj, target) {
for (var k in obj) {
if (obj.hasOwnProperty(k))
if (obj[k] === target)
return path + "['" + k + "']"
else if (typeof obj[k] === "object") {
var result = search(path + "['" + k + "']", obj[k], target);
if (result)
return result;
}
}
return false;
}
//Then for evry node that you need you can call the search() function.
var path = search(path, data, x);
console.log(path); //data['key1']['children']['key4']

I think this is what you're asking about, you can use Object.keys to get the properties of an object, then loop through them afterward.
var data = {
"products": {
"laptop": [{
"brand": "sony",
"price": "$1000"
}, {
"brand": "acer",
"price": "$400"
}],
"cellphone": [{
"brand": "iphone",
"price": "$800"
}, {
"brand": "htc",
"price": "$500"
}],
"tablets": [{
"brand": "iPad",
"price": "$800"
}, {
"brand": "htc-tab",
"price": "$500"
}]
}
}
var typesOfProducts = Object.keys(data.products)
console.log(typesOfProducts)
document.getElementById('output').textContent = typesOfProducts.toString()
//Then, to loop through
var i = -1,
len = typesOfProducts.length
function handleProduct(productType) {
console.log("This is the " + productType + " data.")
console.log(data.products[productType])
}
while (++i < len) {
handleProduct(typesOfProducts[i])
}
<div id="output"></div>

It sounds like what you're looking for is just an array of the keys of the "products" object. Example:
Products: ["laptop", "cellphone", "tablets"];
If so, I would just run your json object through javascript's Object.keys() method.
var jsonObj = JSON.parse(http_request.responseText);
var products = Object.keys(jsonObj.products);
// products = ["laptop", "cellphone", "tablets"];

Push Unique Objects to JavaScript Array

How do I push an object into an specified array that only updates that array? My code pushes an object and updates all arrays, not just the specified one.
Here is the structure of the data:
{
"d": {
"results": [
{
"Id": 1,
"cost": "3",
"item": "Project 1",
"fiscalyear": "2014",
"reportmonth": "July"
}
]
}
}
Here is a sample of the desired, wanted results:
{
"Project 1": [
{
"date": "31-Jul-14",
"rating": "3"
},
{
"date": "31-Aug-14",
"rating": "4"
}
],
"Project 2": [
{
"date": "31-Jul-14",
"rating": "2"
}
]
}
This is my attempt:
var results = data.d.results;
var date;
var projectObj = {},
projectValues = {},
project = '';
var cost = '',
costStatus = '';
for (var i = 0, m = results.length; i < m; ++i) {
project = results[i]['item'];
if (!projectObj.hasOwnProperty(project)) {
projectObj[project] = [];
}
// use Moment to get and format date
date = moment(new Date(results[i]['reportmonth'] + ' 1,' + results[i]['fiscalyear'])).endOf('month').format('DD-MMM-YYYY');
// get cost for each unique project
costStatus = results[i]['cost'];
if (costStatus == null || costStatus == 'N/A') {
cost = 'N/A';
}
else {
cost = costStatus;
}
projectValues['rating'] = cost;
projectValues['date'] = date;
projectObj[project].push(projectValues);
}
Here is a Fiddle with the undesired, unwanted results:
https://jsfiddle.net/yh2134jn/4/
What am I doing wrong?

That is because You do not empty it new iteration. Try this:
for (var i = 0, m = results.length; i < m; ++i) {
projectValues = {};
project = results[i]['item'];
....
}

JSON to filtered Array in JavaScript

I have this JSON string:
[
{
"pk": "alpha",
"item": [{
"child": "val"
}]
},
{
"pk": "beta",
"attr": "val",
"attr2": [
"child1"
]
},
{
"pk": "alpha",
"anotherkey": {
"tag": "name"
}
}
]
And I need to produce a filtered array without repeated PK, in the example above the last entry: "pk": "alpha","anotherkey": { ... should be eliminated from the output array. All this using JavaScript. I tried with the object JSON.parse but it returns many key,value pairs that are hard to filter for example "key=2 value=[object Object]".
Any help is greatly appreciated.

var data = JSON.parse(jsonString);
var usedPKs = [];
var newData = [];
for (var i = 0; i < data.length; i++) {
if (usedPKs.indexOf(data[i].pk) == -1) {
usedPKs.push(data[i].pk);
newData.push(data[i]);
}
}
// newData will now contain your desired result

var contents = JSON.parse("your json string");
var cache = {},
results = [],
content, pk;
for(var i = 0, len = contents.length; i < len; i++){
content = contens[i];
pk = content.pk;
if( !cache.hasOwnPropery(pk) ){
results.push(content);
cache[pk] = true;
}
}
// restuls

<script type="text/javascript">
// Your sample data
var dataStore = [
{
"pk": "alpha",
"item": [{
"child": "val"
}]
},
{
"pk": "beta",
"attr": "val",
"attr2": [
"child1"
]
},
{
"pk": "alpha",
"anotherkey": {
"tag": "name"
}
}
];
// Helper to check if an array contains a value
Array.prototype.contains = function(obj) {
var i = this.length;
while (i--) {
if (this[i] == obj) {
return true;
}
}
return false;
}
// temp array, used to store the values for your needle (the value of pk)
var tmp = [];
// array storing the keys of your filtered objects.
var filteredKeys = [];
// traversing you data
for (var i=0; i < dataStore.length; i++) {
var item = dataStore[i];
// if there is an item with the same pk value, don't do anything and continue the loop
if (tmp.contains(item.pk) === true) {
continue;
}
// add items to both arrays
tmp.push(item.pk);
filteredKeys.push(i);
}
// results in keys 0 and 1
console.log(filteredKeys);
</script>