Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
Javascript Articles
Page 311 of 534
Inserting empty string in place of repeating values in JavaScript
We have to write a function that takes in an array, removes all duplicates from it and inserts the same number of empty strings at the end.For example: If we find 4 duplicate values we have to remove then all and insert four empty strings at the end.Therefore, let’s write the code for this function −ExampleThe code for this will be −const arr = [1, 2, 3, 1, 2, 3, 2, 2, 3, 4, 5, 5, 12, 1, 23, 4, 1]; const deleteAndInsert = arr => { const creds = arr.reduce((acc, val, ind, array) => { ...
Read MoreDetecting the largest element in an array of Numbers (nested) in JavaScript
We have to write a simple function in JavaScript that takes in an array of Numbers (nested to any level) and return the greatest number present in the array.For example: If the input array is −const arr = [ 34, 65, 67, [ 43, 76, 87, 23, 56, 7, [ 54, 7, 87, 23, 79, 994, 2 ], 54 ], 54, 4, 2 ];Then the output should be −994We will use recursion to find the greatest number in the array.ExampleThe code ...
Read MoreDetecting the first non-unique element in array in JavaScript
We are required to write a function that returns the index of the very first element that appears at least twice in the array. If no element appears more than once, we have to return -1. We have to do this in constant space (i.e., without utilizing extra memory).So, let's write the solution for this problem.We will use a for loop to iterate over the array and use the Array.prototype.lastIndexOf() method to check for duplicacy.ExampleThe code for this will be −const arr1 = [0, 1, 1, 2, 3, 4, 4, 5]; const firstRedundant = arr => { for(let i ...
Read MoreUsing recursion to remove consecutive duplicate entries from an array in JavaScript
We are supposed to write a function that takes in an array of number/string literals. The function should remove all the redundant consecutive elements of the array without using extra memory space.For example, if the input array is −const arr = [17, 17, 17, 12, 12, 354, 354, 1, 1, 1];Then the output should be −const output = [17, 12, 354, 1];Therefore, let’s write the code for this function −ExampleThe code for this will be −const arr = [17, 17, 17, 12, 12, 354, 354, 1, 1, 1]; const comp = (arr, len = 0, deletable = false) => { ...
Read MoreArray flattening using loops and recursion in JavaScript
We are required to write a JavaScript array function that takes in a nested array with false values as well and returns an array with all the elements present in the array without any nesting.For example: If the input is −const arr = [[1, 2, 3], [4, 5, [5, false, 6, [5, 8, null]]], [6]];Then the output should be −const output = [1, 2, 3, 4, 5, false, 6, 5, 8, null, 6];Therefore, let’s write the code for this function −ExampleThe code for this will be −const arr = [[1, 2, 3], [4, 5, [5, false, 6, [5, 8, null]]], ...
Read MoreIf the element repeats, remove all its instances from array in JavaScript
We are required to write a function that takes in an array and returns a new array that have all duplicate values removed from it. The values that appeared more than once in the original array should not even appear for once in the new array.For example, if the input is −const arr = [763, 55, 43, 22, 32, 43, 763, 43];The output should be −const output = [55, 22, 32];Array.prototype.indexOf(): It returns the index of first occurrence of searched string if it exists, otherwise -1.Array.prototype.lastIndexOf(): It returns the index of last occurrence of searched string if it exists, otherwise ...
Read MoreKeeping only alphanumerals in a JavaScript string in JavaScript
We are required to write a JavaScript function that takes in a string that might contain some special characters.The function should return a new string should have all special characters replaced with their corresponding ASCII value.Therefore, let’s write the code for this function −ExampleThe code for this will be −const str = 'Th!s !s @ str!ng th@t cont@!ns some special characters!!'; const specialToASCII = str => { let res = ''; for(let i = 0; i < str.length; i++){ if(+str[i] || str[i].toLowerCase() !== str[i].toUpperCase() || str[i] === ' '){ res += ...
Read MoreListing all the prime numbers upto a specific number in JavaScript
We are required to write a JavaScript function that takes in a number, say n, and returns an array containing all the prime numbers upto n.For example: If the number n is 24.Then the output should be −const output = [2, 3, 5, 7, 11, 13, 17, 19, 23];Therefore, let’s write the code for this function −ExampleThe code for this will be −const num = 24; const isPrime = num => { let count = 2; while(count < (num / 2)+1){ if(num % count !== 0){ count++; continue; }; return false; }; return true; }; const primeUpto = num => { if(num < 2){ return []; }; const res = [2]; for(let i = 3; i
Read MoreAND product of arrays in JavaScript
We have an array of arrays of boolean like this −const arr = [[true, false, false], [false, false, false], [false, false, true]];We are required to write a function that merges this array of arrays into a one-dimensional array by combining the corresponding elements of each subarray using the AND (&&) operator.Let’s write the code for this function. We will be using Array.prototype.reduce() function to achieve this.ExampleThe code for this will be −const arr = [[true, false, false], [false, false, false], [false, false, true]]; const andMerge = (arr = []) => { return arr.reduce((acc, val) => { ...
Read MoreDeviations in two JavaScript arrays in JavaScript
We have two arrays of numbers like these −const arr1 = [12, 54, 2, 4, 6, 34, 3]; const arr2 = [54, 2, 5, 12, 4, 1, 3, 34];We are required to write a JavaScript function that takes in two such arrays and returns the element from arrays that are not common to both.Therefore, let’s write the code for this function −ExampleThe code for this will be −const arr1 = [12, 54, 2, 4, 6, 34, 3]; const arr2 = [54, 2, 5, 12, 4, 1, 3, 34]; const difference = (first, second) => { const res = []; ...
Read More