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Web Development Articles
Page 235 of 801
Finding sum of alternative elements of the array in JavaScript
We are required to write a JavaScript function that takes in an array of Numbers as the only argument. The function should calculate and return the sum of alternative elements of the array. For example − If the input array is − const arr = [1, 2, 3, 4, 5, 6, 7]; Then the output should be − 1 + 3 + 5 + 7 = 16 Method 1: Using for Loop with Index Check This approach uses a for loop and checks if the index is even to ...
Read MoreConverting object to 2-D array in JavaScript
In JavaScript, we often need to convert objects into 2D arrays where each sub-array contains a key-value pair. This is useful for data processing, iteration, or when working with APIs that expect array formats. Suppose we have an object that contains information about the weather of a city: const obj = { city: "New Delhi", maxTemp: 32, minTemp: 21, humidity: 78, aqi: 456, day: 'Tuesday', }; We need to convert this object into a 2D array where ...
Read MoreConverting array of arrays into an object in JavaScript
Converting an array of arrays into an object is a common task in JavaScript when dealing with key-value pair data. This is particularly useful when transforming data from APIs or CSV-like structures. Suppose we have an array of arrays that contains the performance of a cricket player like this: const arr = [ ['Name', 'V Kohli'], ['Matches', 13], ['Runs', 590], ['Highest', 183], ['NO', 3], ['SR', 131.5] ]; We need to write a JavaScript function that takes such ...
Read MoreTrim off '?' from strings in JavaScript
We are required to write a JavaScript function that takes in a string as the only argument. The string is likely to contain question marks (?) in the beginning and the end. The function should trim off all these question marks from the beginning and the end keeping everything else in place. For example − If the input string is − const str = '??this is a ? string?'; Then the output should be − 'this is a ? string' Method 1: Using Regular Expressions The simplest approach uses ...
Read MoreInsert a character at nth position in string in JavaScript
We are required to write a JavaScript function that takes in a string as the first argument and a number as the second argument and a single character as the third argument, let's call this argument char. The number is guaranteed to be smaller than the length of the array. The function should insert the character char after every n characters in the string and return the newly formed string. For example − If the arguments are − const str = 'NewDelhi'; const n = 3; const char = ' '; Then the ...
Read MoreComparing the performance of recursive and looped factorial function in JavaScript
We will be writing two JavaScript functions, the job of both the functions will be to take in a number and return its factorial. The first function should make use of a for loop or while loop to compute the factorial. Whereas the second function should compute the factorial using a recursive approach. Lastly, we should compare the times taken by these functions over a large number of iterations. Iterative Factorial Function The iterative approach uses a simple for loop to calculate the factorial: const factorial = (num = 1) => { ...
Read MorePrimality test of numbers in JavaScript
A prime number (or a prime) is a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers. All other natural numbers greater than 1 are called composite numbers. A primality test is an algorithm for determining whether an input number is prime. We are required to write a JavaScript function that takes in a number and checks whether it is a prime or not. Basic Primality Test Algorithm The most efficient approach is to check divisibility up to the square root of the number, skipping even numbers after checking for 2. ...
Read MoreEuclidean Algorithm for calculating GCD in JavaScript
In mathematics, Euclid's algorithm is a method for computing the greatest common divisor (GCD) of two numbers, the largest number that divides both of them without leaving a remainder. The Euclidean algorithm is based on the principle that the greatest common divisor of two numbers does not change if the larger number is replaced by its difference with the smaller number. For example, 21 is the GCD of 252 and 105 (as 252 = 21 × 12 and 105 = 21 × 5), and the same number 21 is also the GCD of 105 and 252 − 105 ...
Read MoreChecking power of 2 using bitwise operations in JavaScript
We are required to write a JavaScript function that takes in a number and determines whether or not it is a power of two. For example − f(23) = false f(16) = true f(1) = true f(1024) = true Understanding Powers of Two in Binary Powers of two in binary form always have exactly one bit set to 1: 1: 0001 2: 0010 4: 0100 8: 1000 16: 10000 32: 100000 The Bitwise Approach ...
Read MoreRegular Expression Matching in JavaScript
Regular expression matching is a fundamental concept in computer science where we match an input string against a pattern containing special characters. In JavaScript, we can implement custom regex matching using dynamic programming to handle patterns with . (any character) and * (zero or more occurrences). Problem Definition Given an input string str and a pattern p, implement regular expression matching with support for: . → Matches any single character * → Matches zero or more of the preceding element The matching must cover the entire input string ...
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