Found 9150 Articles for Object Oriented Programming

Sorting objects by numeric values - JavaScript

AmitDiwan
Updated on 18-Sep-2020 13:21:13

461 Views

Suppose we have an object like this −const obj = {    key1: 56,    key2: 67,    key3: 23,    key4: 11,    key5: 88 };We are required to write a JavaScript function that takes in this object and returns a sorted array like this −const arr = [11, 23, 56, 67, 88];Here, we sorted the object values and placed them in an array.ExampleFollowing is the code −const obj = {    key1: 56,    key2: 67,    key3: 23,    key4: 11,    key5: 88 }; const sortObject = obj => {    const arr = Object.keys(obj).map(el => {       return obj[el];    });    arr.sort((a, b) => {       return a - b;    });      return arr; }; console.log(sortObject(obj));OutputThis will produce the following output in console −[ 11, 23, 56, 67, 88 ]

Convert JS array into an object - JavaScript

AmitDiwan
Updated on 18-Sep-2020 13:19:56

330 Views

Suppose, we have an array of objects like this −const arr = [    {id: 1, name: "Mohan"},    {id: 2, name: "Sohan"},    {id: 3, name: "Rohan"} ];We are required to write a function that takes one such array and constructs an object from it with the id property as key and name as valueThe output for the above array should be −const output = {1:{name:"Mohan"}, 2:{name:"Sohan"}, 3:{name:"Rohan"}}ExampleFollowing is the code −const arr = [    {id: 1, name: "Mohan"},    {id: 2, name: "Sohan"},    {id: 3, name: "Rohan"} ]; const arrayToObject = arr => {    const ... Read More

Sum arrays repeated value - JavaScript

AmitDiwan
Updated on 18-Sep-2020 13:18:44

127 Views

Suppose, we have an array of objects like this −const arr = [    {'ID-01':1},    {'ID-02':3},    {'ID-01':3},    {'ID-02':5} ];We are required to add the values for all these objects together that have identical keysTherefore, for this array, the output should be −const output = [{'ID-01':4}, {'ID-02':8}];We will loop over the array, check for existing objects with the same keys, if they are there, we add value to it otherwise we push new objects to the array.ExampleFollowing is the code −const arr = [    {'ID-01':1},    {'ID-02':3},    {'ID-01':3},    {'ID-02':5} ]; const indexOf = function(key){   ... Read More

Group values on same property - JavaScript

AmitDiwan
Updated on 18-Sep-2020 13:17:16

315 Views

Suppose we have an array like this −const arr = [    {unit: 35, brand: 'CENTURY'},    {unit: 35, brand: 'BADGER'},    {unit: 25, brand: 'CENTURY'},    {unit: 15, brand: 'CENTURY'},    {unit: 25, brand: 'XEGAR'} ];We are required to write a function that groups all the brand properties of objects whose unit property is the same.Like for the above array, the new array should be −const output = [    {unit: 35, brand: 'CENTURY, BADGER'},    {unit: 25, brand: 'CENTURY, XEGAR'},    {unit: 15, brand: 'CENTURY'} ];We will loop over the array, search for the object with unit value ... Read More

Checking an array for palindromes - JavaScript  

AmitDiwan
Updated on 18-Sep-2020 13:15:59

968 Views

We are required to write a JavaScript function that takes in an array of String / Number literals and returns a subarray of all the elements that were palindrome in the original array.For example −If the input array is −const arr = ['carecar', 1344, 12321, 'did', 'cannot'];Then the output should be −const output = [12321, 'did'];We will create a helper function that takes in a number or a string and checks if it’s a boolean or not. Then we will loop over the array, filter the palindrome elements and return the filtered arrayExampleFollowing is the code −const arr = ['carecar', ... Read More

Fetching JavaScript keys by their values - JavaScript

AmitDiwan
Updated on 18-Sep-2020 13:14:25

190 Views

Suppose, we have an object like this −const products = {    "Pineapple":38,    "Apple":110,    "Pear":109 };All the keys are unique in themselves and all the values are unique in themselves. We are required to write a function that accepts a value and returns its keyFor example: findKey(110) should return −"Apple"We will approach this problem by first reverse mapping the values to keys and then simply using object notations to find their values.ExampleFollowing is the code −const products = {    "Pineapple":38,    "Apple":110,    "Pear":109 }; const findKey = (obj, val) => {    const res = {}; ... Read More

Splitting strings based on multiple separators - JavaScript

AmitDiwan
Updated on 18-Sep-2020 13:13:24

597 Views

We are required to write a JavaScript function that takes in a string and any number of characters specified as separators. Our function should return a splitted array of the string based on all the separators specified.For example −If the string is −const str = 'rttt.trt/trfd/trtr, tr';And the separators are −const sep = ['/', '.', ', '];Then the output should be −const output = [ 'rttt', 'trt', 'trfd', 'trtr' ];ExampleFollowing is the code −const str = 'rttt.trt/trfd/trtr, tr'; const splitMultiple = (str, ...separator) => {    const res = [];    let start = 0;    for(let i = 0; ... Read More

Convert number to tens, hundreds, thousands and so on - JavaScript

AmitDiwan
Updated on 18-Sep-2020 13:11:59

1K+ Views

We are required to write a function that, given a number, say, 123, will output an array −[100,20,3]Basically, the function is expected to return an array that contains the place value of all the digits present in the number taken as an argument by the function.We can solve this problem by using a recursive approach.ExampleFollowing is the code −const num = 123; const placeValue = (num, res = [], factor = 1) => {    if(num){       const val = (num % 10) * factor;       res.unshift(val);       return placeValue(Math.floor(num / 10), res, factor * 10);    };    return res; }; console.log(placeValue(num));OutputThis will produce the following output in console −[ 100, 20, 3 ]

Splitting an array based on its first value - JavaScript

AmitDiwan
Updated on 18-Sep-2020 13:10:51

351 Views

Suppose we have an array of arrays of numbers like this −const arr = [[1, 45], [1, 34], [1, 49], [2, 34], [4, 78], [2, 67], [4, 65]];Each subarray is bound to contain strictly two elements. We are required to write a function that constructs a new array where all second elements of the subarrays that have similar first value are grouped together.Therefore, for the array above, the output should look like −const output = [    [45, 34, 49],    [34, 67],    [78, 65] ];We can make use of the Array.prototype.reduce() method that takes help of a Map() ... Read More

Creating a two-dimensional array with given width and height in JavaScript

AmitDiwan
Updated on 18-Sep-2020 13:08:31

701 Views

We are required to write a JavaScript function that creates a multi-dimensional array based on some inputs. It should take in three elements, namely −row − the number of subarrays to be present in the array, col − the number of elements in each subarrayval minus; the val of each element in the subarraysFor example, if the three inputs are 2, 3, 10Then the output should be −const output = [[10, 10, 10], [10, 10, 10]];ExampleFollowing is the code −const row = 2; const col = 3; const val = 10; const constructArray = (row, col, val) => {   ... Read More

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