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Suppose we have a string with digits like this −const str = '11222233344444445666';We are required to write a JavaScript function that takes in this string and returns an object that represents the count of each number in the string.Therefore, for this string, the output should be −const output = { "1": 2, "2": 4, "3": 3, "4": 7, "5": 1, "6": 3 };ExampleFollowing is the code −const str = '11222233344444445666'; const mapString = str => { const map = {}; for(let i = 0; i < str.length; i++){ map[str[i]] ... Read More
IntroductionThe require_once statement in PHP is similar in functioning to that of require statement. Only difference is, if a file has been already included for processing, it will not be included again.Note that a file included with either include or require statement will also be not included again even if require_once statement is used.Other behaviour of require_once statement is similar to require statement .require_once ExampleIn following example main php script includes test.phpExample Live Demo //test.php OutputThis will produce following result when main script is run from command line −inside main script now including with require_once test.php script File included try to include ... Read More
We are required to write a JavaScript function that takes in an array of numbers that may contain some duplicate numbers.Our function should return the sum of all the unique elements (elements that only appear once in the array) present in the array.For example −If the input array is −const arr = [2, 5, 5, 3, 2, 7, 4, 9, 9, 11];Then the output should be 25We will simply use a for loop, iterate the array and return the sum of unique elements.ExampleFollowing is the code −const arr = [2, 5, 5, 3, 2, 7, 4, 9, 9, 11]; const ... Read More
Suppose we have an array of objects like this −const arr = [{a: 2, b: 5, c: 6}, {a:3, b: 4, d:1}, {a: 1, d: 2}];Each object is bound to have unique keys in itself (for it to be a valid object), but two different objects can have the common keys (for the purpose of this question)We are required to write a JavaScript function that takes in one such array and returns an object with all the unique keys present in the array and their values cumulative sum as the valueTherefore, the resultant object should look like −const output = ... Read More
IntroductionEffect of require statement is similar to include statement in PHP. However, there is one main difference. If the parser fails to find required file, it produces a fatal error thereby termination of current script. The include statement on the other hand emits a warning in case of failure to find file and execution of current script continues.PHP parser tries to locate the file in current folder by default and further in directories mentioned in include_path setting of php.ini, as in case of include statement. If file asked for is not available in current folder as well as include_path folders, ... Read More
Suppose we have an object like this −const obj = { key1: 56, key2: 67, key3: 23, key4: 11, key5: 88 };We are required to write a JavaScript function that takes in this object and returns a sorted array like this −const arr = [11, 23, 56, 67, 88];Here, we sorted the object values and placed them in an array.ExampleFollowing is the code −const obj = { key1: 56, key2: 67, key3: 23, key4: 11, key5: 88 }; const sortObject = obj => { const arr = Object.keys(obj).map(el => { return obj[el]; }); arr.sort((a, b) => { return a - b; }); return arr; }; console.log(sortObject(obj));OutputThis will produce the following output in console −[ 11, 23, 56, 67, 88 ]
Suppose, we have an array of objects like this −const arr = [ {id: 1, name: "Mohan"}, {id: 2, name: "Sohan"}, {id: 3, name: "Rohan"} ];We are required to write a function that takes one such array and constructs an object from it with the id property as key and name as valueThe output for the above array should be −const output = {1:{name:"Mohan"}, 2:{name:"Sohan"}, 3:{name:"Rohan"}}ExampleFollowing is the code −const arr = [ {id: 1, name: "Mohan"}, {id: 2, name: "Sohan"}, {id: 3, name: "Rohan"} ]; const arrayToObject = arr => { const ... Read More
Suppose, we have an array of objects like this −const arr = [ {'ID-01':1}, {'ID-02':3}, {'ID-01':3}, {'ID-02':5} ];We are required to add the values for all these objects together that have identical keysTherefore, for this array, the output should be −const output = [{'ID-01':4}, {'ID-02':8}];We will loop over the array, check for existing objects with the same keys, if they are there, we add value to it otherwise we push new objects to the array.ExampleFollowing is the code −const arr = [ {'ID-01':1}, {'ID-02':3}, {'ID-01':3}, {'ID-02':5} ]; const indexOf = function(key){ ... Read More
IntroductionJust as the include statement, include_once also transfers and evaluates script written in one file in another, the difference in two lies in the fact that include_once prevents same file from reloading if already done. As the name indicates, a file will be included only once even if one tries to issue include instruction again.The include_once statement is typically used to set up global variables, enable libraries or any such activity that is expected to be done in the beginning of execution of application.Other than this, behaviour of include_once statement is similar to include statement.include_once ExampleIn following example testscript.php is ... Read More
Suppose we have an array like this −const arr = [ {unit: 35, brand: 'CENTURY'}, {unit: 35, brand: 'BADGER'}, {unit: 25, brand: 'CENTURY'}, {unit: 15, brand: 'CENTURY'}, {unit: 25, brand: 'XEGAR'} ];We are required to write a function that groups all the brand properties of objects whose unit property is the same.Like for the above array, the new array should be −const output = [ {unit: 35, brand: 'CENTURY, BADGER'}, {unit: 25, brand: 'CENTURY, XEGAR'}, {unit: 15, brand: 'CENTURY'} ];We will loop over the array, search for the object with unit value ... Read More