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Javascript Articles
Page 237 of 534
Create palindrome by changing each character to neighboring character in JavaScript
ProblemWe are required to write a JavaScript function that takes in a string. Our function can do the following operations on the string −each character MUST be changed either to the one before or the one after in the alphabet."a" can only be changed to "b" and "z" to "y".Our function should return True if at least one of the outcomes of these operations is a palindrome or False otherwise.ExampleFollowing is the code − Live Democonst str = 'adfa'; const canFormPalindrome = (str = '') => { const middle = str.length / 2; for(let i = 0; i < ...
Read MoreFinding value of a sequence for numbers in JavaScript
ProblemConsider the following sequence sum −$$seq(n,\:p)=\displaystyle\sum\limits_{k=0} \square(-1)^{k}\times\:p\:\times 4^{n-k}\:\times(\frac{2n-k}{k})$$We are required to write a JavaScript function that takes in the numbers n and p returns the value of seq(n, p).ExampleFollowing is the code − Live Democonst n = 12; const p = 70; const findSeqSum = (n, p) => { let sum = 0; for(let k = 0; k
Read MoreRemoving n characters from a string in alphabetical order in JavaScript
ProblemWe are required to write a JavaScript function that takes in a lowercase alphabet string and number num.Our function should remove num characters from the array in alphabetical order. It means we should first remove ‘a’ if they exist then ‘b’ , ‘c’ and so on until we hit the desired num.ExampleFollowing is the code − Live Democonst str = 'abascus'; const num = 4; const removeAlphabetically = (str = '', num = '') => { const legend = "abcdefghijklmnopqrstuvwxyz"; for(let i = 0; i < legend.length; i+=1){ while(str.includes(legend[i]) && num > 0){ ...
Read MoreFinding two prime numbers with a specific number gap in JavaScript
ProblemWe are required to write a JavaScript function that takes in a number, gap as the first argument and a range array of two numbers as the second argument. Our function should return an array of all such prime pairs that have an absolute difference of gap and falls between the specified range.ExampleFollowing is the code − Live Democonst gap = 4; const range = [20, 200]; const primesInRange = (gap, [left, right]) => { const isPrime = num => { for(let i = 2; i < num; i++){ if(num % i === ...
Read MoreFinding two missing numbers that appears only once and twice respectively in JavaScript
ProblemWe are required to write a JavaScript function that takes in an array in which all the numbers appear thrice except one which appears twice and one which appears only one. Our function should find and return these two numbers.ExampleFollowing is the code − Live Democonst arr = [1, 1, 1, 2, 2, 3]; const findMissing = (arr = []) => { let x = 0; let y = 0; for(let i = 0; i < arr.length; i++){ if(arr.filter(a => a === arr[i]).length === 2){ y = arr[i]; }; if(arr.filter(b => b === arr[i]).length === 1){ x = arr[i]; }; }; return [x, y]; }; console.log(findMissing(arr));OutputFollowing is the console output −[3, 2]
Read MoreCreating a Projectile class to calculate height horizontal distance and landing in JavaScript
ProblemWe are required to write a JavaScript class, Projectile, which takes in 3 arguments when initialized −starting height (0 ≤ h0 < 200)starting velocity (0 < v0 < 200)angle of the projectile when it is released (0° < a < 90°, measured in degrees).We need to write the following method for the Projectile class.A horiz method, which also takes in an argument t and calculates the horizontal distance that the projectile has traveled. [takes in a double, returns a double]ExampleThe code for this class will be − Live Democlass Projectile{ constructor(h, u, ang){ this.h = h; ...
Read MoreCutting off number at each digit to construct an array in JavaScript
ProblemWe are required to write a JavaScript function that takes in a number. Our function should return an array of strings containing the number cut off at each digit.ExampleFollowing is the code − Live Democonst num = 246; const cutOffEach = (num = 1) => { const str = String(num); const res = []; let temp = ''; for(let i = 0; i < str.length; i++){ const el = str[i]; temp += el; res.push(temp); }; return res; }; console.log(cutOffEach(num));OutputFollowing is the console output −[ '2', '24', '246' ]
Read MoreWriting a custom URL shortener function in JavaScript
ProblemWe are required to write two JavaScript functions −First function should take in a long url and return a short url that corresponds to it.The second function should take in the short url and redirect to the original url.ExampleFollowing is the code − Live Democonst url = 'https://www.google.com/search?client=firefox-b-d&q=google+search'; const obj = {}; const urlShortener = (longURL = '') => { let shortURL = "short.ly/" + longURL.replace(/[^a-z]/g, '').slice(-4); if(!obj[shortURL]){ obj[shortURL] = longURL; }; return shortURL; } const urlRedirector = (shortURL = '') => { return obj[shortURL]; }; const short = urlShortener(url); const ...
Read MoreGenerating the sequence of first n look and say numbers in JavaScript
ProblemIn mathematics, the look-and-say sequence is the sequence of integers beginning as follows −1, 11, 21, 1211, 111221, 312211, …To generate a member of the sequence from the previous member, we read off the digits of the previous member, counting the number of digits in groups of the same digit.For instance, the next number to 1211 is −111221Because if we read the digit of 1211 louder it will be −One one, one two, two one which gives us 111221We are required to write a JavaScript function that takes in a number n and returns the first n terms of look ...
Read MoreRectifying the time string in JavaScript
ProblemWe are required to write a JavaScript function that takes in a time string in “HH:MM:SS” format.But there was a problem in addition, so many of the time strings are broken which means the MM part may exceed 60, and SS part may as well exceed 60.Our function should make required changes to the string and return the new rectified string.For instance −"08:11:71" -> "08:12:11"ExampleFollowing is the code − Live Democonst str = '08:11:71'; const rectifyTime = (str = '') => { if(!Boolean(str)){ return str; }; const re = /^(\d\d):(\d\d):(\d\d)$/; if (!re.test(str)){ ...
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