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Object Oriented Programming Articles
Page 47 of 589
Sorting only a part of an array JavaScript
We are required to write a JavaScript function that takes in an array of strings as the first argument and two numbers as second and third argument respectively. The purpose of our function is to sort the array. But we have to sort only that part of the array that falls between the start and end indices specified by second and third argument. Keeping all the other elements unchanged. For example: const arr = ['z', 'b', 'a']; sortBetween(arr, 0, 1); This function should sort the elements at 0 and 1 index only. And the ...
Read MoreHow to transform two or more spaces in a string in only one space? JavaScript
In JavaScript, you can transform multiple consecutive spaces in a string into a single space using regular expressions with the replace() method. This is useful for cleaning up text input or formatting strings consistently. The Regular Expression Approach The most effective method uses the regular expression /\s{2, }/g where: \s matches any whitespace character (spaces, tabs, newlines) {2, } matches two or more consecutive occurrences g is the global flag to replace all instances Method 1: Using replace() with Regular Expression ...
Read MoreGroup a JavaScript Array
Grouping JavaScript arrays by a specific property is a common requirement when working with complex data structures. In this tutorial, we'll learn how to group array elements by the tableName property and restructure the data. Problem Statement Suppose we have a JavaScript array with objects containing table data: const data = [ { "dataId": "1", "tableName": "table1", "column": "firstHeader", "rows": ...
Read MoreSort array based on min and max date in JavaScript?
When working with arrays of date strings, you often need to find the oldest (minimum) and newest (maximum) dates. JavaScript provides several approaches to accomplish this task efficiently. const arr = [ "2017-01-22 00:21:17.0", "2017-01-27 11:30:23.0", "2017-01-24 15:53:21.0", "2017-01-27 11:34:18.0", "2017-01-26 16:55:48.0", "2017-01-22 11:57:12.0", "2017-01-27 11:35:43.0" ]; We need to write a JavaScript function that takes such an array, finds the oldest and newest date, and returns an object containing both dates. Using Array.reduce() Method The reduce() method provides an ...
Read MoreCalculate average from JSON data based on multiple filters JavaScript
When working with JSON data, you often need to filter, group, and calculate averages based on multiple criteria. This article demonstrates how to group objects by multiple fields and compute averages while handling edge cases like undefined values. Problem Statement Given an array of supplier objects, we need to: Group objects with the same "SupplierName" and "Category" Sum their points together (ignoring undefined values) Calculate the average points for each group Return the grouped results with totals and averages ...
Read MoreCounting prime numbers from 2 upto the number n JavaScript
We are required to write a JavaScript function that takes in a number, say n, as the first and the only argument. The function should then return the count of all the prime numbers from 2 up to the number n (exclusive). For example: For n = 10, the output should be: 4 (2, 3, 5, 7) For n = 1, the output should be: 0 Understanding Prime Numbers A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. The first few prime ...
Read MoreConvert the number or boolean type JSON object from string type to its original in JavaScript
Suppose we have a JSON object where numeric and boolean values are stored as strings: const obj = {"name":"sam", "age":"24", "isMarried":"false"}; console.log(obj); { name: 'sam', age: '24', isMarried: 'false' } Here, the age property should be a number and isMarried should be a boolean. Our goal is to write a function that converts these string values back to their correct data types. Method 1: Using parseInt and Boolean Conversion This approach checks each property and converts numeric strings to numbers and boolean strings to booleans: const obj = { ...
Read MoreSearch from an array of objects via array of string to get array of objects in JavaScript
Filtering an array of objects based on keys from another array is a common requirement in JavaScript. This tutorial shows how to extract matching objects using various approaches. Problem Statement Given an array of strings and an array of objects, we need to filter objects whose KEY property exists in the string array: const searchKeys = ['1956888670', '2109171907', '298845084']; const users = [ { KEY: '1262875245', VALUE: 'Vijay Kumar Verma' }, { KEY: '1956888670', VALUE: 'Sivakesava Nallam' }, { KEY: '2109171907', VALUE: 'udm analyst' ...
Read MoreConvert array with duplicate values to object with number of repeated occurrences in JavaScript
When working with arrays that contain duplicate values, you often need to count occurrences and convert them into a structured format. This article shows how to transform an array with duplicates into an array of objects containing each unique value and its count. Problem Statement Suppose we have an array with duplicate entries like this: const arr = ['California', 'Texas', 'Texas', 'Texas', 'New York', 'Missouri', 'New Mexico', 'California']; console.log("Original array:", arr); Original array: [ 'California', 'Texas', 'Texas', 'Texas', 'New York', ...
Read MoreFilter nested object by keys using JavaScript
When working with arrays of objects in JavaScript, you often need to filter them based on specific criteria. This article demonstrates how to filter an array of objects by checking if their title property contains any of the specified search terms. Problem Statement Suppose we have an array of objects like this: const arr = [{ 'title': 'Hey', 'foo': 2, 'bar': 3 }, { 'title': 'Sup', 'foo': 3, 'bar': 4 }, { ...
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