Javascript-Arrays

Write a JavaScript function to check whether an input is an array or not

function checkArray(arr) { if (Array.isArray(arr)) { return "array"; } else return "not an array";

} checkArray([1, 2, 3, 4, 5])

2.Write a JavaScript function to clone an array

function cloneArray(arr) { var newarr =[] return newarr.concat(arr) } var arr1 =[1, 2, 3, 4, 5] var arr2=cloneArray(arr1) arr1.pop() console.log(arr1) console.log(arr2)

3.Write a JavaScript function to get the first element of an array. Passing a parameter 'n' will return the first 'n' elements of the array

4.Write a JavaScript function to get the last element of an array. Passing a parameter 'n' will return the last 'n' elements of the array

function getLastElements(arr, n) { return arr.reverse().slice(0, n).reverse() } console.log(getLastElements([1, 2, 3, 4, 5], 3)) console.log(getLastElements([7, 9, 0, -2])); console.log(getLastElements([], 3)); console.log(getLastElements([7, 9, 0, -2], 3)); console.log(getLastElements([7, 9, 0, -2], 6)); console.log(getLastElements([7, 9, 0, -2], -3));

5.Write a simple JavaScript program to join all elements of the following array into a string.

function join_string(arr){

return arr.join(",") } myColor = ["Red", "Green", "White", "Black"]; join_string(myColor)

6.Write a JavaScript program which accept a number as input and insert dashes (-) between each two even numbers. For example if you accept 025468 the output should be 0-254-6-8.

function withDash(num) { var withdash = ''

for (let i = 0; i < num.length; i++){ if(num[i]%2===0 && num[i+1]%2===0){ withdash += ${num[i]}- } else{ withdash += num[i] } } return withdash

} withDash('02546')

Write a JavaScript program to sort the items of an array.

function sortArray(arr){ return arr.sort(function(a,b){ return a-b; }) } sortArray([ -3, 8, 7, 6, 5, -4, 3, 2, 1 ])

8.Write a JavaScript program to find the most frequent item of an array (Important)

function mostFrequent(arr) { let valores = {} arr.sort().forEach(item => { valores[item] = (valores[item] ? valores[item] + 1 : 1) });

const values = Object.values(valores) const maxvalues = Math.max(...values) const findindex = values.findIndex(function(e1){ return e1===maxvalues}) console.log(findindex)

return Object.entries(valores)[findindex]

}

mostFrequent([3, 'a', 'a', 'a', 2, 3, 'a', 3, 'a', 2, 4, 9, 3])

Write a JavaScript program which accept a string as input and swap the case of each character. For example if you input 'The Quick Brown Fox' the output should be 'tHE qUICK bROWN fOX'

function swapFirst(str) { var arr = str.split(' ') var newarr = [] for (let i = 0; i < arr.length;i++) { newarr.push(arr[i].charAt(0).toLowerCase()+arr[i].toUpperCase().slice(1)) } return newarr.join(' ')

} swapFirst('The Quick Brown Fox')

Write a JavaScript program which prints the elements of the following array.

function showList(arr) { for (let i = 0; i < arr.length; i++) { console.log('row', i) for (let j = 0; j < arr[i].length; j++) { console.log(arr[i][j]) }

} }

var a = [[1, 2, 1, 24], [8, 11, 9, 4], [7, 0, 7, 27], [7, 4, 28, 14], [3, 10, 26, 7]] showList(a)

Write a JavaScript program to find the sum of squares of a numeric vector

function sumOfSquares(arr){ var sum= 0 for(let i of arr){ sum += i*i

} return sum } sumOfSquares([1,2,3])

12.Write a JavaScript program to compute the sum and product of an array of integers

function sumOfSquares(arr){ var sum= 0 var mul =1 for(let i of arr){ sum += i mul *= i

} return console.log(sum,mul) } sumOfSquares([1,2,3,4])

Write a JavaScript program to add items in an blank array and display the items

14.Write a JavaScript program to remove duplicate items from an array

function removeDuplicates(arr) { var newarr = [] for (let x of arr) { if (!newarr.includes(x)) { newarr.push(x) } } return newarr } removeDuplicates([1, 2, 3, 4, 2, 4, 3, 1, 6, 7, 8, 2, 2, 2, 2])

We have the following arrays : Go to the editor color = ["Blue ", "Green", "Red", "Orange", "Violet", "Indigo", "Yellow "]; o = ["th","st","nd","rd"] Write a JavaScript program to display the colors in the following way : "1st choice is Blue ." "2nd choice is Green." "3rd choice is Red."

var color = ["Blue", "Green", "Red", "Orange", "Violet", "Indigo", "Yellow"]; var ordinal = ["th","st","nd","rd"]; var output = ""; for (var i = 0; i < color.length; i++) { switch(i){ case 0: output += "1" + ordinal[1] + " choice is " + color[i]+'\n'; break; // you need to fix < b r > codes here. case 1: output += "2" + ordinal[2] + " choice is " + color[i]+'\n'; break; case 2: output += "3" + ordinal[3] + " choice is " + color[i]+'\n'; break; default: output += i+1 + ordinal[0] + " choice is " + color[i]+'\n'; break; } } console.log(output)

Find the leap years in a given range of years.

function range(startY, endY){ for(let i = startY; i <= endY; i++){ if((i % 4 === 0 && i % 100 !== 0) || (i % 100 === 0 && i % 400 === 0)){ console.log(i) } } } range(2000,4000)

Write a JavaScript program to shuffle an array

function shuffle(arr) { for (let i = 0; i < arr.length; i++) { var temp; let rnd = Math.floor(Math.random() * arr.length) temp = arr[i]; arr[i] = arr[rnd] arr[rnd] = temp

} return arr } shuffle([1, 2, 3, 4, 5])

Write a JavaScript program to perform a binary search

function binarySearch(arr, n) { var min = 0 var max = arr.length - 1 while (min <= max) { var mid = Math.floor((min + max) / 2) if (arr[mid] < n) { console.log('if1') min = mid + 1 } else if (arr[mid] > n) { console.log('if2') max = mid - 1 } else if (arr[mid] == n) { console.log('if3') return mid; } } return The value doen't exist in the array; }

var items = [1, 2, 3, 4, 5, 6, 7, 8] binarySearch(items, 7)

19.There are two arrays with individual values, write a JavaScript program to compute the sum of each individual index value from the given arrays

function sumOfArrays(arr1, arr2) {

var newarr = [] if (arr1.length > arr2.length) { for (let i = 0; i < arr1.length; i++) { if (arr2[i] === undefined) { arr2[i] = 0 }

  newarr.push(arr1[i] + arr2[i] + '')
}

} else if (arr1.length < arr2.length) {

for (let i = 0; i < arr2.length; i++) {
  if (arr1[i] === undefined) {
    arr1[i] = 0
  }
  newarr.push(arr1[i] + arr2[i] + '')
}

} else { for (let i = 0; i < arr2.length; i++) { newarr.push(arr1[i] + arr2[i]) } }

return newarr }

array1 = [1, 0, 2, 3, 4]; array2 = [3, 5, 6, 7]; sumOfArrays(array1, array2)

Write a JavaScript program to find duplicate values in a JavaScript array

Write a JavaScript program to flatten a nested (any depth) array. If you pass shallow, the array will only be flattened a single level.

function flatten(arr){

var arr1 =arr.toString().split(',').map(Number) return arr1 } console.log(flatten([1, [2], [3, [[4]]],[5,6]]));

Write a JavaScript program to compute the union of two arrays

function union(arr1, arr2) { for (let i of arr2) { if (!arr1.includes(i)) { arr1.push(i) } } return arr1 } console.log(union([1, 2, 3], [100, 2, 1, 10]));

Write a JavaScript function to find the difference of two arrays

function difference(arr1, arr2) { arr1 = arr1.toString().split(',').map(Number) arr2 = arr2.toString().split(',').map(Number) var newarr = [];

for (let i of arr2) { if (!arr1.includes(i)) { newarr.push(i) } } return newarr } console.log(difference([1, 2, 3, 4, 5], [1, [2], [3, [[4]]], [5, 6]]));

Write a JavaScript function to remove. 'null', '0', '""', 'false', 'undefined' and 'NaN' values from an array

function notinclude(arr) { let newarr = [] for (let i of arr) { if (i) { newarr.push(i) } } return newarr } console.log(notinclude([NaN, 0, 15, false, -22, '', undefined, 47, null]));

Write a JavaScript function to sort the following array of objects by title value

console.log(arryObjectSort(library))

26 .Write a JavaScript program to find a pair of elements (indices of the two numbers) from an given array whose sum equals a specific target number.

function sumOfConsecutives(arr, value) { var newarr = [] for (let i = 0; i < arr.length - 1; i++) { if (arr[i] + arr[i + 1] == value) { newarr.push(arr[i], arr[i + 1]) } } return newarr

} var numbers = [10, 20, 10, 40, 50, 60, 70] var target = 50 console.log(sumOfConsecutives(numbers, target))

27.Write a JavaScript function to retrieve the value of a given property from all elements in an array.

function notinclude(arr) { let newarr = [] for (let i of arr) { if (i) { newarr.push(i) } } return newarr } console.log(notinclude([NaN, 0, 15, false, -22, '', undefined, 47, null]));

Write a JavaScript function to find the longest common starting substring in a set of strings

Write a JavaScript function to fill an array with values (numeric, string with one character) on supplied bounds.(Important)

function num_string_range(start, end, step) { let a = start.charCodeAt(0) let b = end.charCodeAt(0) let newarr =[] newarr = Array.from({ length: (b - a) / step + 1 }, (_, i) => a + (i * step)).map(x => String.fromCharCode(x)); return newarr } console.log(num_string_range('a', 'z', 2));

Write a JavaScript function to merge two arrays and removes all duplicates elements.

function merge_array(arr1,arr2){ for(let i of arr1){ if(!arr2.includes(i)){ arr2.push(i) } } return arr2 } var array1 = [1, 2, 3]; var array2 = [2, 30, 1]; console.log(merge_array(array1, array2));

Write a JavaScript function to remove a specific element from an array.

function remove_array_element(arr, n) { var newarr = [] for (let i of arr) { if (i !== n) { newarr.push(i) } } return newarr } console.log(remove_array_element([2, 5, 9, 6], 5));

Write a JavaScript function to find an array contains a specific element

function contains(arr, n) { var newarr = [] for (let i of arr) { if (i == n) { return true } } return false } arr = [2, 5, 9, 6]; console.log(contains(arr, 5));

Write a JavaScript script to empty an array keeping the original

var arr = [1, 3, 6, 3, -5]; console.log(arr); arr.length = 0; console.log(arr);

34.Write a JavaScript function to get nth largest element from an unsorted array

function nthHighest(numbers, n) { var sorted = numbers.sort(function (a, b) { return a-b; });

return sorted[n - 1];

}

console.log(nthHighest([43, 56, 23, 89, 88, 90, 99, 652], 1));

Write a JavaScript function to get a random item from an array.

function randomitem(arr) { let rnd = Math.floor(Math.random() * arr.length) return arr[rnd] } console.log(randomitem([1, 4, 6, 9, 12, 43, 76, 98]))

Write a JavaScript function to create a specified number of elements with pre-filled numeric value array

function array_filled(num1, n) {

let array = new Array(num1).fill(n) return array; } console.log(array_filled(6, 0)); console.log(array_filled(4, 11));

Write a JavaScript function to create a specified number of elements with pre-filled string value array

function array_filled(num1, n) {

let array = new Array(num1).fill(n) return array; } console.log(array_filled(4, 'password'));

Write a JavaScript function to move an array element from one position to another.

function move(arr, from, to) { var elem = arr.splice(from, 1)[0]; if (to < 0) to += 1; arr.splice(to, 0, elem); return arr; } console.log(move([10, 20, 30, 40, 50], 0, 2)); //[20, 30, 10, 40, 50]

Write a JavaScript function to filter false, null, 0 and blank values from an array

function notinclude(arr) { let newarr = [] for (let i of arr) { if (i) { newarr.push(i) } } return newarr } console.log(notinclude([NaN, 0, 15, false, -22, '', undefined, 47, null]));

Write a JavaScript function to generate an array of specified length, filled with integer numbers, increase by one from starting position

function array_range(start, len) { var arr = new Array(len); for (var i = 0; i < len; i++, start++) { arr[i] = start; } return arr; } console.log(array_range(1, 4));

Write a JavaScript function to generate an array between two integers of 1 step length.

function array_generate(start, end, step) {

const length = Math.floor((end-start)/step)+1 if(start>end){ step = -step } return Array.from(Array(length), (_, i) => start + step * i) } console.log(array_generate(1, 10, 2)) console.log(array_generate(-6, 7,2));

Write a JavaScript function to find the unique elements from two arrays.

function findUnique(arr1,arr2){ arr1 = arr1.toString().split(',').map(Number) arr2 = arr2.toString().split(',').map(Number)

let newarr = []

for(let i = 0;i<arr1.length;i++){ if(!newarr.includes(arr1[i])){ newarr.push(arr1[i]) } } for(let i = 0;i<arr2.length;i++){ if(!newarr.includes(arr2[i])){ newarr.push(arr2[i]) } } return newarr

}

console.log(findUnique([1, 2, 3], [100, 2, 1, 10])); console.log(findUnique([1, 2, 3, 4, 5], [1, [2], [3, [[4]]],[5,6]]));

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