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
-
Economics & Finance
Object Oriented Programming Articles
Page 145 of 589
Reorder array based on condition in JavaScript?
Let's say we have an array of objects that contains the scores of some players in a card game: const scorecard = [{ name: "Zahir", score: 23 }, { name: "Kabir", score: 13 }, { name: "Kunal", score: 29 }, { name: "Arnav", score: 42 }, { name: "Harman", score: 19 }, { name: ...
Read MoreHow to match strings that aren't entirely digits in JavaScript?
In JavaScript, you can use regular expressions to match strings that contain non-digit characters. This is useful when parsing complex data strings where you need to identify values that aren't purely numeric. Problem Statement Consider this complex string containing various data types: studentId:"100001",studentName:"John Smith",isTopper:true,uniqueId:10001J-10001,marks:78,newId:"4678" We want to extract values that contain characters other than digits, excluding boolean values and null. Using Regular Expression The following regular expression matches strings that aren't entirely digits: var regularExpression = /(?
Read MoreCount unique elements in array without sorting JavaScript
When working with arrays containing duplicate values, counting unique elements is a common task. Let's explore different approaches to count unique elements in an array without sorting it first. Consider this sample array with duplicate values: const arr = ['Cat', 'Dog', 'Cat', 'Elephant', 'Dog', 'Grapes', 'Dog', 'Lion', 'Grapes', 'Lion']; console.log('Original array:', arr); Original array: ['Cat', 'Dog', 'Cat', 'Elephant', 'Dog', 'Grapes', 'Dog', 'Lion', 'Grapes', 'Lion'] Using Array.reduce() and lastIndexOf() This approach uses lastIndexOf() to identify the last occurrence of each element, ensuring each unique value is counted only once: const ...
Read MoreHow to combine two arrays into an array of objects in JavaScript?
Combining two arrays into an array of objects is a common task in JavaScript. This allows you to pair corresponding elements from both arrays into structured data. Using map() with Object Creation The map() method creates a new array by transforming each element. We can use it to combine arrays into objects: var firstArray = ['John', 'David', 'Bob']; var secondArray = ['Mike', 'Sam', 'Carol']; var arrayOfObjects = firstArray.map(function(value, index) { return { first: value, second: ...
Read MoreTop n max value from array of object JavaScript
Finding the top n objects with maximum values from an array is a common programming task. Let's explore how to get objects with the highest duration values from an array of objects. Problem Statement Given an array of objects, we need to create a function that returns the top n objects based on the highest duration values. const arr = [ {"id":0, "start":0, "duration":117, "slide":4, "view":0}, {"id":0, "start":0, "duration":12, "slide":1, "view":0}, {"id":0, "start":0, "duration":41, "slide":2, "view":0}, {"id":0, "start":0, "duration":29, "slide":3, ...
Read MoreHow to convert an array into a complex array JavaScript?
In JavaScript, converting a flat array into a complex nested array structure involves grouping elements based on specific conditions. A common use case is splitting an array into subarrays when the sum of consecutive elements exceeds a given threshold. Let's say we need to write a function that takes an array of numbers and a number n, where n is the maximum sum allowed for each subarray. The function should break the array into subarrays whenever the sum of consecutive elements would exceed n. Example Problem Given an array and a threshold value, we want to create ...
Read MoreCan JavaScript parent and child classes have a method with the same name?
Yes, JavaScript parent and child classes can have methods with the same name. This concept is called method overriding, where the child class provides its own implementation of a method that already exists in the parent class. Method Overriding Example class Parent { constructor(parentValue) { this.parentValue = parentValue; } // Parent class method showValues() { console.log("The parent method is called....."); ...
Read MoreHow to generate child keys by parent keys in array JavaScript?
Let's say, we have an array of objects representing a hierarchical structure where each object has an id, parent_id, and title: const arr = [ { id: 1, parent_id: 0, title: 'Movies' }, { id: 2, parent_id: 0, title: 'Music' }, { id: 3, parent_id: 1, title: 'Russian movies' }, { id: 4, parent_id: 2, title: 'Russian music' }, { id: 5, parent_id: 3, title: 'New' }, { id: 6, parent_id: 3, title: 'Top10' ...
Read MoreCompare two arrays and get those values that did not match JavaScript
We have two arrays of literals that contain some common values, our job is to write a function that returns an array with all those elements from both arrays that are not common. For example − // if the two arrays are: const first = ['cat', 'dog', 'mouse']; const second = ['zebra', 'tiger', 'dog', 'mouse']; // then the output should be: const output = ['cat', 'zebra', 'tiger'] // because these three are the only elements that are not common to both arrays Let's write the code for this − We will spread the two ...
Read MoreRemove values in an array by comparing the items 0th index in JavaScript?
When working with arrays of sub-arrays, you may need to remove duplicates based on the first element (0th index) of each sub-array. This is common when dealing with data like subject-marks pairs where you want only unique subjects. Let's say the following is our array: var subjectNameAlongWithMarks = [ ["JavaScript", 78], ["Java", 56], ["JavaScript", 58], ["MySQL", 77], ["MongoDB", 75], ["Java", 98] ]; console.log("Original array:", subjectNameAlongWithMarks); Original array: [ ...
Read More