This question already has answers here:
Comparing two arrays of objects, and exclude the elements who match values into new array in JS
(6 answers)
Closed 5 years ago.
I want to find unique elements in a which do not exist in b on the basis of name property
EXPECTED OUTPUT
var data= [{"name":"rashffffish","color":"blue" }];
var a =[{"name":"sam","color":"red" }, {"name":"rash","color":"blue" },{"name":"rashffffish","color":"blue" }];
var b = [{"name":"sam","color":"red" },{"name":"rash","color":"red" }];
var data = [];
b.map((n)=>{
for(i=0;i<a.length;i++) {
if(n.name!= a[i].name){
data.push(a[i]);
}
}
})
console.log(data);
Use Array#filter to filter the a array and pass a predicate which uses Array#some to try to find an item. When there is no match, get those items
const a =[
{"name":"sam","color":"red" },
{"name":"rash","color":"blue" },
{"name":"rashffffish","color":"blue" }
];
const b = [
{"name":"sam","color":"red" },
{"name":"rash","color":"red" }
];
const filtered = a.filter(itemA => !b.some(itemB => itemA.name === itemB.name));
console.log(filtered);
From your code...
var a = [{
"name": "sam",
"color": "red"
}, {
"name": "rash",
"color": "blue"
}, {
"name": "rashffffish",
"color": "blue"
}];
var b = [{
"name": "sam",
"color": "red"
}, {
"name": "rash",
"color": "red"
}];
var data = a;
b.forEach((n) => {
for (i = 0; i < data.length; i++) {
if (n.name === a[i].name) {
var ind= data.indexOf(a[i]);
data.splice(ind, 1);
}
}
})
console.log(data);
Related
I have an array that I'm retrieving from an API. The array looks like this:
[{
"name": "Rachel",
"count": 4,
"fon": "46-104104",
"id": 2
},
{
"name": "Lindsay",
"count": 2,
"fon": "43-053201",
"id": 3
},
{
"name": "Michael",
"count": 5,
"fon": "46-231223",
"id": 4
}]
Then I loop through the array to create an array containing only the names.
function buildName(data) {
for (var i = 0; i < data.length; i++) {
nameList.push(data[i].name)
}
}
This also works so far, but I would like to create an array in which each name occurs as often as the object count says.
For example, the name Michael should appear five times in the array and Lindsay twice.
[
"Rachel",
"Rachel",
"Rachel",
"Rachel",
"Lindsay",
"Lindsay",
"Michael",
"Michael",
"Michael",
"Michael"
"Michael"
]
For each object create a new array using count, and then fill it with the name.
If you use flatMap to iterate over the array of objects. It will return a new array of nested objects but then flatten them into a non-nested structure.
const data=[{name:"Rachel",count:4,fon:"46-104104",id:2},{name:"Lindsay",count:2,fon:"43-053201",id:3},{name:"Michael",count:5,fon:"46-231223",id:4}];
const out = data.flatMap(obj => {
return new Array(obj.count).fill(obj.name)
});
console.log(out);
I've upgraded your functions but you can use the map method
function buildName(data){
for (let i = 0; i < data.length; i++){
let numToLoop = data[i].count
let name = data[i].name
for (let z = 0; z < +numToLoop; z++){
nameList.push(name)
}
}
}
Use an inner while loop inside the for loop:
const data = [{
"name": "Rachel",
"count": 4,
"fon": "46-104104",
"id": 2
},
{
"name": "Lindsay",
"count": 2,
"fon": "43-053201",
"id": 3
},
{
"name": "Michael",
"count": 5,
"fon": "46-231223",
"id": 4
}]
function buildName(data){
const result = [];
for (let i = 0; i < data.length; i += 1) {
let item = data[i];
let count = item.count;
while (count > 0) {
result.push(item.name);
count -= 1;
}
}
return result;
}
console.log(buildName(data));
Just add an inner loop with as many iterations as the "count" property in the object:
function buildName(data) {
const nameList = [];
for (var i = 0; i < data.length; i++) {
for (let j = 0; j < data[i].count; j++) {
nameList.push(data[i].name);
}
}
return nameList;
}
For fun
import { pipe } from 'fp-ts/lib/function';
import { chain, replicate } from 'fp-ts/lib/Array';
const arr = ...
const result = pipe(
arr,
chain(i => replicate(i.count, i.name))
);
You can use .flapMap() for that:
const arr = [{ "name": "Rachel", "count": 4, "fon": "46-104104", "id": 2 }, { "name": "Lindsay", "count": 2, "fon": "43-053201", "id": 3 }, { "name": "Michael", "count": 5, "fon": "46-231223", "id": 4 }];
const result = arr.flatMap(({count, name}) => Array(count).fill(name));
console.log(result);
Effectively you turn every element into an array of the the name property repeated count times which is then flattened into a single array.
It can be done via creating an array with repeated names in this way:
Array(count).fill(name)
Then you have to spread it into resulting array.
You can try this one-liner
const getNames = (data) =>
data.reduce(
(names, { name, count }) => [...names, ...Array(count).fill(name)],
[]
)
Note that a pure function is presented here, which is generally the preferred way of writing code. However, updating your example code might look like this
const getNames = (data) =>
data.reduce(
(names, { name, count }) => [...names, ...Array(count).fill(name)],
[]
)
function buildName(data) {
nameList = getNames(data)
}
This question already has answers here:
Javascript - Return only unique values in an array of objects
(6 answers)
Closed 2 years ago.
How do I calculate the unique values of an object property when I have an array of objects?
let organisations = [
{
"id": 1,
"name": "nameOne",
},
{
"id": 2,
"name": "nameTwo",
},
{
"id": 3,
"name": "nameOne",
}
]
In this case, how do I calculate the number of unique organisation names. The answer here is two, because there are two unique names.
This doesn't work
var counts = this.filteredExtendedDeals.reduce(
(organisations, name) => {
counts[name] = (counts[name] || 0) + 1;
return counts;
},
{}
);
return Object.keys(counts);
You could reduce the list into a Set and then grab the size.
const organisations = [
{ "id": 1, "name": "nameOne" },
{ "id": 2, "name": "nameTwo" },
{ "id": 3, "name": "nameOne" }
];
const uniqueItems = (list, keyFn) => list.reduce((resultSet, item) =>
resultSet.add(typeof keyFn === 'string' ? item[keyFn] : keyFn(item)),
new Set).size;
console.log(uniqueItems(organisations, 'name'));
console.log(uniqueItems(organisations, ({ name }) => name));
This question already has answers here:
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)
This question already has answers here:
How can I remove a specific item from an array in JavaScript?
(142 answers)
Closed 4 years ago.
{
"list": [{
"name": "car",
"status": "Good",
"time": "2018-11-02T03:26:34.350Z"
},
{
"name": "Truck",
"status": "Ok",
"time": "2018-11-02T03:27:23.038Z"
},
{
"name": "Bike",
"status": "NEW",
"time": "2018-11-02T13:08:49.175Z"
}
]
}
How do I remove just the car info from the array.
To achieve expected result, use filter option to filter out car related values
var obj = {"list":[ {"name":"car", "status":"Good", "time":"2018-11-02T03:26:34.350Z"}, {"name":"Truck", "status":"Ok", "time":"2018-11-02T03:27:23.038Z"}, {"name":"Bike", "status":"NEW", "time":"2018-11-02T13:08:49.175Z"} ]}
let result = {
list: []
}
result.list.push(obj.list.filter(v => v.name !=='car'))
console.log(result)
codepen - https://codepen.io/nagasai/pen/MzmMQp
Option 2: without using filter as requested by OP
Use simple for loop to achieve same result
var obj = {"list":[ {"name":"car", "status":"Good", "time":"2018-11-02T03:26:34.350Z"}, {"name":"Truck", "status":"Ok", "time":"2018-11-02T03:27:23.038Z"}, {"name":"Bike", "status":"NEW", "time":"2018-11-02T13:08:49.175Z"} ]}
let result = {
list: []
}
for(let i =0; i< obj.list.length; i++){
if(obj.list[i].name !== 'car' ){
result.list.push(obj.list[i])
}
}
console.log(result)
const obj = JSON.parse(jsonString);
let yourArray = obj.list;
let filteredArray = yourArray.filter(elem => elem.name !== "car");
I've got an array of three people. I want to add a new key to multiple objects at once based on an array of indices. Clearly my attempt at using multiple indices doesn't work but I can't seem to find the correct approach.
var array = [
{
"name": "Tom",
},
{
"name": "Dick",
},
{
"name": "Harry",
}
];
array[0,1].title = "Manager";
array[2].title = "Staff";
console.log(array);
Which returns this:
[
{
"name": "Tom",
},
{
"name": "Dick",
"title": "Manager"
},
{
"name": "Harry",
"title": "Staff"
}
]
But I'd like it to return this.
[
{
"name": "Tom",
"title": "Manager"
},
{
"name": "Dick",
"title": "Manager"
},
{
"name": "Harry",
"title": "Staff"
}
]
You cannot use multiple keys by using any separator in arrays.
Wrong: array[x, y]
Correct: array[x] and array[y]
In your case, it will be array[0].title = array[1].title = "manager";
1st method::
array[0].title = "Manager";
array[1].title = "Manager";
array[2].title = "Staff";
array[0,1] will not work.
2nd method::
for(var i=0;i<array.length;i++) {
var msg = "Manager";
if(i===2) {
msg = "Staff"
}
array[i].title = msg
}
You can use a helper function like this
function setMultiple(array, key, indexes, value)
{
for(i in array.length)
{
if(indexes.indexOf(i)>=0){
array[i][key] = value;
}
}
}
And then
setMultiple(array, "title", [0,1], "Manager");
Try this: `
for (var i=0; var<= array.length; i++){
array[i].title = "manager";
}`
Or you can change it around so var is less than or equal to any n range of keys in the index.
EDIT: instead make var <= 1. The point is to make for loops for the range of indices you want to change the title to.
Assuming that you have a bigger set of array objects.
var array = [
{
"name": "Tom",
},
{
"name": "Dick",
},
{
"name": "Harry",
},
.
.
.
];
Create an object for the new keys you want to add like so:
let newKeys = {
'Manager': [0,2],
'Staff': [1]
}
Now you can add more such titles here with the required indexes.
with that, you can do something like:
function addCustomProperty(array, newKeys, newProp) {
for (let key in newKeys) {
array.forEach((el, index) => {
if (key.indexOf(index) > -1) { // if the array corresponding to
el[newProp] = key // the key has the current array object
} // index, then add the key to the
}) // object.
}
return array
}
let someVar = addCustomProperty(array, newKeys, 'title')