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Suppose we have an array of arrays that contains the marks of some students in some subjects like this −const arr = [ ["English", 52], ["Hindi", 154], ["Hindi", 241], ["Spanish", 10], ["French", 65], ["German", 98], ["Russian", 10] ];We are required to write a JavaScript function that takes in one such array and returns an object of objects.The return object should contain an object for each unique subject, and that object should contain information like the number of appearances of that language, sum of total marks and the average.ExampleThe code for this will be −const arr = [ ["English", 52], ... Read More
We are required to write a JavaScript function that takes in a number as one and the only argument. The function should then return a randomly generated string of the length specified by the argument.The character set to be used for the string generation should only contain uppercase and lowercase alphabets (no whitespaces, punctuations or numerals).ExampleThe code for this will be −const num = 13; const randomString = (len = 1) => { const charSet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'; let randomString = ''; for (let i = 0; i < len; i++) { let randomPoz ... Read More
Cartesian ProductThe Cartesian product of two sets (arrays) A and B, denoted A × B, is the set (array) of all ordered pairs (a, b) where a is in A and b is in B.In simpler terms, a cartesian product of two arrays is a permutation of all possible arrays of two elements whose first element belongs to the first array and the second element belongs to the second array.For example − If the two arrays are −const arr1 = [1, 2, 3]; const arr2 = [4, 5];Then their cartesian product will be −const product = [[1, 4], [1, 5], ... Read More
Suppose, we have an array of Strings that contains month-year combined strings like this −const arr = ["2009-feb", "2009-jan", "2010-mar", "2010-jan", "2011-jul", "2011-sep", "2011-jan", "2012-jan", "2012-dec", "2012-feb", "2013-may", "2013-jul", "2013-jun", "2014-jan", "2014-dec", "2014-may", "2015-may", "2015-jan", "2015-jun", "2016-jan", "2016-dec"];We are required to write a JavaScript function that takes in one such array and sorts these dates in oldest to latest order.ExampleThe code for this will be −const arr = ["2009-feb", "2009-jan", "2010-mar", "2010-jan", "2011-jul", "2011-sep", "2011-jan", "2012-jan", "2012-dec", "2012-feb", "2013-may", "2013-jul", "2013-jun", "2014-jan", "2014-dec", "2014-may", "2015-may", "2015-jan", "2015-jun", "2016-jan", "2016-dec"]; const sorter = (a, b) => { const getDate = ... Read More
Let's say we have such an array −const arr = [A, A, B, B, C, C, D, E];We are required to create an algorithm so that it will find all the combinations that add up to the whole array, where none of the elements are repeated.Example combinations −[A, B, C, D, E] [A, B, C] [A, B, C, D] [A, B, C, E] [A, B, C] [A, B, C] [D, E]Explanation[A, B, C] [A, B, C] [D, E] and [A, B, C] [D, E] [A, B, C] are the same combinations. Also, the ordering with the subsets doesn't matter as ... Read More
We are required to write a JavaScript function that takes in an array of literals as the first argument and a string as the second argument. Our function should return the count of the number of times that string (provided by second argument) appears anywhere in the array.ExampleThe code for this will be −const arr = ["word", "a word", "another word"]; const query = "word"; const findAll = (arr, query) => { let count = 0; count = arr.filter(el => { return el.indexOf(query) != -1; }).length; return count; }; console.log(findAll(arr, query));OutputAnd the output in the console will be −3
Suppose, we have a JSON Array that contains data about some tickets like this −const arr = [ { "quantity": "1", "description": "VIP Ticket to Event" }, { "quantity": "1", "description": "VIP Ticket to Event" }, { "quantity": "1", "description": "VIP Ticket to Event" }, { "quantity": "1", "description": "Regular Ticket to Event" }, { "quantity": "1", "description": "Regular Ticket to ... Read More
We are required to write a JavaScript function that takes in two arrays of equal length. The function should multiply the corresponding (by index) values in each, and sum the results.For example: If the input arrays are −const arr1 = [2, 3, 4, 5]; const arr2 = [4, 3, 3, 1];then the output should be 34, because,(4*2+3*3+4*3+5*1) = 34ExampleThe code for this will be −const arr1 = [2, 3, 4, 5]; const arr2 = [4, 3, 3, 1]; const produceAndAdd = (arr1 = [], arr2 = []) => { let sum = 0; for(let i=0; i < arr1.length; i++) { const product = (arr1[i] * arr2[i]); sum += product; }; return sum; }; console.log(produceAndAdd(arr1, arr2));OutputAnd the output in the console will be −34
We are required to write a JavaScript function that splits an Array of numbers into N groups, which must be ordered from larger to smaller groups.For example, in the below code, split an Array of 12 numbers into 5 Arrays, and the result should be evenly split, from large (group) to small:const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]; const output = [[1, 2, 3] [4, 5, 6] [7, 8] [9, 10] [11, 12]];The function should take in the array as the first argument and the number of partitions as the second argument.ExampleThe ... Read More
We are required to write a JavaScript function that takes in a stringified mathematical equation. The function should return the result of the equation provided to the function.For example: If the equation is −const str = '1+23+4+5-30';Then the output should be 3ExampleThe code for this will be −const str = '1+23+4+5-30'; const compute = (str = '') => { let total = 0; str = str.match(/[+\−]*(\.\d+|\d+(\.\d+)?)/g) || []; while (str.length) { total += parseFloat(str.shift()); }; return total; }; console.log(compute(str));OutputAnd the output in the console will be −3