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Using array, How to print name of students who has highest marks in Javascript?

The code i tried
function findHighest(){
var highest = 0; // assum min 0
var highestItem;
$('tr').each(function(index, item){
if(index > 0){
var math = $(item).find('td').eq(1).text();
var eng = $(item).find('td').eq(2).text();
var lit = $(item).find('td').eq(3).text();
//alert(math)
var sum = parseFloat(math) + parseFloat(eng) + parseFloat(lit)
if (sum > highest){
highest = sum;
highestItem = item;
}
}
})
$(highestItem).css({ 'font-style': 'italic', 'color': 'red' });
}
I am trying to find name of student who got highest marks in class in at least two subjects in JavaScript?

const highestMarks=[];
const studentsWithHighestMarks=[];
const students = [{ name: "mini", subject: [{ maths : 20}, {english: 23}, { science: 25}, { sports: 24}] }, { name: "jerry", subject: [{ maths : 22}, {english: 20}, { science: 20}, { sports: 21}] }, { name: "john", subject: [{ maths : 23}, {english: 25}, { science: 20}, { sports: 21}] }];
students.forEach(student=>{
student.subject.forEach(subject=>{
for(let key in subject){
var index = highestMarks.findIndex(obj => {
return obj.subject === key
});
if (index===-1) {
highestMarks.push({
subject:key,
marks:subject[key],
students:[student.name]
})
}else if(highestMarks[index].marks<subject[key]){
highestMarks[index].marks=subject[key];
highestMarks[index].students=[student.name];
}
else if(highestMarks[index].marks==subject[key]){
highestMarks[index].marks=subject[key];
highestMarks[index].students.push(student.name);
}
}
})
});
students.forEach(student=>{
let count=0;
highestMarks.forEach(item=>{
if(item.students.includes(student.name)){
count++;
}
});
if(count>=2){
studentsWithHighestMarks.push(student.name)
}
})
console.log(studentsWithHighestMarks)

const subjectsConsidering = 2;
const getStudentMarks = (student) => {
const studentMarksList = [];
student.subject.forEach((subjectData) => {
studentMarksList.push(Object.values(subjectData)[0]);
});
const sum = studentMarksList.sort().reverse().reduce((sum, a, index) => {
// restrict only for first 2 subjects
if (index < subjectsConsidering) {
return sum + a;
}
return sum + 0;
});
return sum;
}
students.sort((studentA, studentB) => {
//return 0 for equal marks
return getStudentMarks(studentA) > getStudentMarks(studentB) ? -1 : 1;
});
console.log(students);
//This gives the sorted array of students having the highest marks in at least 2 subjects.

// Transform the data into a more manageable format
// { "subject": [["name", grade], ["name", grade], ["name", grade]] }
let transformed = students.reduce(
(data, student) => {
student.subject.forEach(subject => {
const key = keys(subject)[0];
const grade = [student.name, subject[key]];
if (!(key in data)) {
data[key] = [];
}
data[key].push(grade);
})
return data;
},
{}
)
// Utility function to compare grades
function gradeCompare(a, b) {
return a[1] > b[1] ? -1 : 1;
}
// List the top student in each subject
let names = Object.keys(transformed).map((subject) => {
return transformed[subject].sort(gradeCompare)[0][0];
});
// names :: [ "john", "john", "mini", "mini" ]
// Count the student names
let counts = names.reduce((acc, current) => {
acc[current] = (acc[current] || 0) + 1;
return acc;
}, {});
// counts :: { john: 2, mini: 2 }
// Find the maximum occurring count
let maxCount = Math.max(...Object.values(counts));
// maxCount :: 2
// Filter the keys that have that count
let topStudents = Object.keys(counts).filter(k => counts[k] === maxCount);
// topStudents :: [ "john", "mini" ]

How to get object property list data

I have a list of objects. Every object has a property which is a list of elements:
{ name : 'Club 01'
, id : 1
, form : 45
, points : 0
, tactics : 'neutral'
, played : 0
, gameset : 0
, playedWith : [ 8, 1, 2, 3 ]
}
I want to go through the list and console log all existing elements:
for (let a = 0; a<clubs.width; a++) {
for (let b = 0; b<clubs[a].playedWith.width; b++) {
console.log(clubs[a].playedWith[b]);
}
}
when i do it for one item, this works. however when i do it with a loop as aboce, this brings me to
undefined
Whats wrong with my code? How do i console log all items within playedWith property?

Elikill58 is right. Arrays have length property, not width property.
So your code would work well this way:
for (let a = 0; a < clubs.length; a++){
for (let b = 0; b < clubs[a].playedWith.length; b++){
console.log(clubs[a].playedWith[b]);
}
}
Also, if you want to iterate through all items in the array, just for the sake of simplicity, you can write it like so:
for (const club of clubs) {
for (const width of club.playedWith) {
console.log(width);
}
}

You have to use length instead of width for both loop.
Here is an example :
var clubs = [
{ name : 'Club 01'
, id : 1
, form : 45
, points : 0
, tactics : 'neutral'
, played : 0
, gameset : 0
, playedWith : [ 8, 1, 2, 3 ]
}
];
for (let a = 0; a < clubs.length; a++) {
for (let b = 0; b < clubs[a].playedWith.length; b++) {
console.log(clubs[a].playedWith[b]);
}
}

let b = {
name: 'Club 01',
id: 1,
form: 45,
points: 0,
tactics: 'neutral',
played: 0,
gameset: 0,
playedWith: [8, 1, 2, 3],
move: function() {
return `
${ this.name }and
${this.id }and
${ this.form }and
${ this.points }and
${ this.tactics }and
${ this.played }and
${ this.gameset }and
${ this.playedWith }`
}
};
console.log(b.move())
for (var w in b) {
console.log(${w}:${b.move()})
}

Your best bet is to just do this:
Object.keys(data).forEach((key, i) => {
console.log("Property: " + key, "\nValue: ", data[key])
})
This will give you the property and value. You can also tweak this to have more robust logic for finding or parsing different data types.
You have an array in one of your properties. You can handle it like this.
let clubs = [ {}, {} ]
clubs.forEach((club, i) => {
if (club && Array.isArray(club) || typeof club !== 'object') {
return;
// Stop loop bc club is not an object
}
Object.keys(club).forEach((key, i) => { // Iterate through all the object properties
console.log("Property: " + key, "\nValue: ", club[key])
if (Array.isArray(club[key]) { // Add more conditions or look for certain property names (keys).
console.log('Length of array from property: ', club[key].length)
club[key].map(el => console.log(key + ' value: ' + el))
// You can choose how you want to handle this.
/*
Expected output:
playedWith value: 8
playedWith value: 1
playedWith value: 2
playedWith value: 3
*/
}
})
})

you cant get the array length using width.
try this,
var clubs = [{name: 'Club 01', id:1, form: 45, points: 0, tactics: 'neutral', played: 0, gameset: 0, playedWith: [8,1,2,3]}]
for (let club of clubs) {
for(let playedWothId of club.playedWith){
console.log(playedWothId);
}
}

How to convert an unorganized array into an grouped array by id

I'm trying to create an array that contains objects with an id and amount, grouped by id. The ids needs to be unique. So if there is 2 objects with same id, the amount will be added.
I can do it with nested for-loops, but I find this solution inelegant and huge. Is there a more efficient or cleaner way of doing it?
var bigArray = [];
// big Array has is the source, it has all the objects
// let's give it 4 sample objects
var object1 = {
id: 1,
amount: 50
}
var object2 = {
id: 2,
amount: 50
}
var object3 = {
id: 1,
amount: 150
}
var object4 = {
id: 2,
amount:100
}
bigArray.push(object1,object2,object3,object4);
// organizedArray is the array that has unique ids with added sum. this is what I'm trying to get
var organizedArray = [];
organizedArray.push(object1);
for(var i = 1; i < bigArray.length; i++ ) {
// a boolean to keep track whether the object was added
var added = false;
for (var j = 0; j < organizedArray.length; j++){
if (organizedArray[j].id === bigArray[i].id) {
organizedArray[j].amount += bigArray[i].amount;
added = true;
}
}
if (!added){
// it has object with new id, push it to the array
organizedArray.push(bigArray[i]);
}
}
console.log(organizedArray);

You can definitly make it cleaner and shorter by using reduce, not sure about efficiency though, i would say a traditional for loop is more efficient :
var bigArray = [];
var object1 = {id: 1, amount: 50}
var object2 = {id: 2, amount: 50}
var object3 = {id: 1, amount: 150}
var object4 = {id: 2, amount: 100}
bigArray.push(object1, object2, object3, object4);
var organizedArray = bigArray.reduce((acc, curr) => {
// check if the object is in the accumulator
const ndx = acc.findIndex(e => e.id === curr.id);
if(ndx > -1) // add the amount if it exists
acc[ndx].amount += curr.amount;
else // push the object to the array if doesn't
acc.push(curr);
return acc;
}, []);
console.log(organizedArray)

Rather than an organized array, how about a single object whose keys are the ids and values are the sums.
var bigArray = [
{ id: 1, amount: 50 },
{ id: 2, amount: 50 },
{ id: 1, amount: 150 },
{ id: 2, amount: 100 }
];
let total = {}
bigArray.forEach(obj => {
total[obj.id] = (total[obj.id] || 0) + obj.amount;
});
console.log(total);
If you really need to convert this to an array of objects then you can map the keys to objects of your choosing like this:
var bigArray = [
{ id: 1, amount: 50 },
{ id: 2, amount: 50 },
{ id: 1, amount: 150 },
{ id: 2, amount: 100 }
];
let total = {}
bigArray.forEach(obj => {
total[obj.id] = (total[obj.id] || 0) + obj.amount;
});
console.log(total);
// If you need the organized array:
let organizedArray = Object.keys(total).map(key => ({ id: key, amount: total[key] }));
console.log(organizedArray);

function getUniqueSums(array) {
const uniqueElements = [];
const arrayLength = array.length;
for(let index = 0; index < arrayLength; index++) {
const element = array[index];
const id = element.id;
const uniqueElement = findElementByPropertyValue(uniqueElements, 'id', id);
if (uniqueElement !== null) {
uniqueElement.amount += element.amount;
continue;
}
uniqueElements.push(element);
}
return uniqueElements;
}
function findElementByPropertyValue(array, property, expectedValue) {
const arrayLength = array.length;
for(let index = 0; index < arrayLength; index++) {
const element = array[index];
const value = element[property];
if (value !== expectedValue) {
continue;
}
return element;
}
return null;
}
This is an untested code. You will be able to understand the logic. Logic is almost same yours. But, perhaps a more readable code.

how to count duplicate values object to be a value of object

how to count the value of object in new object values
lets say that i have json like this :
let data = [{
no: 3,
name: 'drink'
},
{
no: 90,
name: 'eat'
},
{
no: 20,
name: 'swim'
}
];
if i have the user pick no in arrays : [3,3,3,3,3,3,3,3,3,3,3,90,20,20,20,20]
so the output should be an array
[
{
num: 3,
total: 11
},
{
num: 90,
total: 1
},
{
num:20,
total: 4
}
];
I would like to know how to do this with a for/of loop
Here is the code I've attempted:
let obj = [];
for (i of arr){
for (j of data){
let innerObj={};
innerObj.num = i
obj.push(innerObj)
}
}

const data = [{"no":3,"name":"drink"},{"no":90,"name":"eat"},{"no":20,"name":"swim"}];
const arr = [3,3,3,3,3,3,3,3,3,3,3,20,20,20,20,80,80];
const lookup = {};
// Loop over the duplicate array and create an
// object that contains the totals
for (let el of arr) {
// If the key doesn't exist set it to zero,
// otherwise add 1 to it
lookup[el] = (lookup[el] || 0) + 1;
}
const out = [];
// Then loop over the data updating the objects
// with the totals found in the lookup object
for (let obj of data) {
lookup[obj.no] && out.push({
no: obj.no,
total: lookup[obj.no]
});
}
document.querySelector('#lookup').textContent = JSON.stringify(lookup, null, 2);
document.querySelector('#out').textContent = JSON.stringify(out, null, 2);
<h3>Lookup output</h3>
<pre id="lookup"></pre>
<h3>Main output</h3>
<pre id="out"></pre>

Perhaps something like this? You can map the existing data array and attach filtered array counts to each array object.
let data = [
{
no: 3,
name: 'drink'
},
{
no:90,
name: 'eat'
},
{
no:20,
name: 'swim'
}
]
const test = [3,3,3,3,3,3,3,3,3,3,3,90,20,20,20,20]
const result = data.map((item) => {
return {
num: item.no,
total: test.filter(i => i === item.no).length // filters number array and then checks length
}
})

You can check next approach using a single for/of loop. But first I have to create a Set with valid ids, so I can discard noise data from the test array:
const data = [
{no: 3, name: 'drink'},
{no: 90, name: 'eat'},
{no: 20, name: 'swim'}
];
const userArr = [3,3,3,3,3,3,3,3,7,7,9,9,3,3,3,90,20,20,20,20];
let ids = new Set(data.map(x => x.no));
let newArr = [];
for (i of userArr)
{
let found = newArr.findIndex(x => x.num === i)
if (found >= 0)
newArr[found].total += 1;
else
ids.has(i) && newArr.push({num: i, total: 1});
}
console.log(newArr);

Printing a tree structure in a list like manner, storing the indent strings (which consist of┣, ┃, ┗ )

I want to store the "node indentation string" for each object, something like this:
foo
┣bar
┃┗baz
┃ ┗qux
┃ ┣quux
┃ ┗corge
┣fizz
┗buzz
Given data for each object:
objects = [
{'id':1,'parent_id':null, 'name':'foo'}
{'id':2,'parent_id':1, 'name':'bar'}
];
Note that I don't want to print anything, I just want to work out the indent as an array of characters for each object:
{'id':6,'parent_id':4, 'name':'corge', 'indent':['┃',' ',' ','┗']}
So far I can only indent them with spaces but no 'pipes' and I am stumped at coming up with a solution. Any help?
I am using JS with Angular if it helps.
EDIT: As requested the code I have so far. I didn't post this at first because I felt that it's a wrong foundation/approach to build on. How it works is pretty trivial: for each object, count it's ancestors and add " "'s accordingly.
// go through all our objects and set their indent strings
setIndents = function()
{
for (var x in objects) {
var o = objects[x];
o.nodes = [];
// push space character for amount of ancestors
numParents = countParents(o, 0);
for (var i = 0; i < numParents; i++)
o.nodes.push(" ");
}
};
// recursively counts how many ancestors until we hit the root
countParents = function(current, count)
{
if (current.parent_id !== null) {
for (var x in objects) {
if (objects[x].id == current.parent_id) {
current = objects[x]; //set as new current
count++;
break;
}
}
return countParents(current, count);
} else {
return count;
}
};

As #JBCP pointed out (see comments) there is a serious flaw in my original code that would break the whole thing if the initial order was anything but perfect.
So here's an updated version, the order of elements can now be random (it still plays a role in such that it indirectly defines the children order, but the tree-structure will be correct).
I also split the functions so that they can be better configured. For example treeIndent now expects a node branch produced by treeify. (Note: the shuffle function is just there to test the order independence)
'use strict';
/**
* #see https://bost.ocks.org/mike/shuffle/
*
* #param array
* #returns {*}
*/
function shuffle(array) {
var m = array.length, t, i;
// While there remain elements to shuffle…
while (m) {
// Pick a remaining element…
i = Math.floor(Math.random() * m--);
// And swap it with the current element.
t = array[m];
array[m] = array[i];
array[i] = t;
}
return array;
}
function treeify(flat) {
var map = { __root__: { children: [] }};
flat.forEach(function (node) {
var
parentId = node.parent_id || '__root__',
id = node.id;
// init parent
if (!map.hasOwnProperty(parentId)) {
map[parentId] = { element: null, children: [] };
}
// init self
if (!map.hasOwnProperty(id)) {
map[id] = { element: null, children: [] };
}
map[id].element = node;
map[parentId].children.push(map[id]);
});
return map.__root__.children;
}
function treeIndent(branch, cfg, decorator, indent)
{
indent = indent || [];
branch.forEach(function (node, i) {
decorator(node.element, indent.concat(
i === branch.length - 1 ? cfg.isLastChild : cfg.hasNextSibling
));
treeIndent(node.children, cfg, decorator, indent.concat(
i === branch.length - 1 ? cfg.ancestorIsLastChild : cfg.ancestorHasNextSibling
));
});
}
var input = [
{ id: 1, parent_id: null, name: 'root' },
{ id: 2, parent_id: 1, name: 'bar' },
{ id: 5, parent_id: 2, name: 'baz' },
{ id: 6, parent_id: 5, name: 'qux' },
{ id: 7, parent_id: 6, name: 'quux' },
{ id: 8, parent_id: 6, name: 'corge' },
{ id: 9, parent_id: 2, name: 'but' },
{ id: 3, parent_id: 1, name: 'fizz' },
{ id: 4, parent_id: 1, name: 'buzz' }
];
var log = document.getElementById('log');
treeIndent(treeify(shuffle(input)), {
hasNextSibling: '├',
isLastChild: '└',
ancestorHasNextSibling: '│',
ancestorIsLastChild: ' '
}, function (element, indent) {
log.innerHTML += indent.join(' ') + ' ' + element.name + "\n";
});
<pre id="log"></pre>
Old answer (broken!):
try the following:
function makeTree(flat) {
var map = { __root__: { children: [] }};
flat.forEach(function (node) {
var
parentId = node.parent_id || '__root__',
id = node.id;
// init parent
if (!map.hasOwnProperty(parentId)) {
map[parentId] = { children: [] };
}
// init self
if (!map.hasOwnProperty(id)) {
map[id] = { children: [] };
}
map[id].element = node;
map[parentId].children.push(map[id]);
});
return map.__root__.children;
}
function injectTreeIndent(input) {
var
levelMap = [],
indicators = {
hasNextSibling: '┣',
isLastChild: '┗',
ancestorHasNextSibling: '┃',
ancestorIsLastChild: ' '
}
;
// apply `indent`
(function traverse(branch, depth) {
branch.forEach(function (node, idx) {
node.element.indent = levelMap.map(function (ancestor) {
return ancestor === indicators.hasNextSibling ? indicators.ancestorHasNextSibling : indicators.ancestorIsLastChild;
});
// if (depth > 0) { // uncomment this, if root elements should have no indentation
node.element.indent.push(
levelMap[depth] = branch.length - 1 > idx ? indicators.hasNextSibling : indicators.isLastChild
);
// }
traverse(node.children, depth + 1);
levelMap.pop();
});
}(makeTree(input), 0));
}
var input = [
{ id: 1, parent_id: null, name: 'foo' },
{ id: 2, parent_id: 1, name: 'bar' },
{ id: 5, parent_id: 2, name: 'baz' },
{ id: 6, parent_id: 5, name: 'qux' },
{ id: 7, parent_id: 6, name: 'quux' },
{ id: 8, parent_id: 6, name: 'corge' },
{ id: 3, parent_id: 1, name: 'fizz' },
{ id: 4, parent_id: 1, name: 'buzz' }
];
injectTreeIndent(input);
makeTree is used to optain a nested structure derived from the given flat data.
injectTreeIndent then traverses that nested structure to inject the required indent informatoin.
demo: http://jsfiddle.net/6R7wf/1/
demo with root elements having no indenation: http://jsfiddle.net/zMY7v/

After for (var i = 0; i < numParents; i++) o.nodes.push(" ");, try
if (o.nodes.length === 1)
o.nodes[0] = "┣";
else if (o.nodes.length > 1) {
o.nodes[0] = "┃";
o.nodes[o.nodes.length - 1] = "┗";
}