13-array-solution.md

Array Questions Solution

Question 1

const arr = [1, 2, 3];
console.log(arr[1]);
console.log(arr.at(1));

Question 2

const arr = [1, 2, 3, 4, 5];
console.log(arr.length);

Question 3

const arr = [1, 2, 3, 4];
for (let i = 0; i < arr.length; i++) {
  console.log(arr[i]);
}

Question 4

const arr = [1, 2, 3, 4, 5, 6];
arr.forEach(test);

function test(num) {
  console.log(num);
}

Question 5

const arr = [1, 2, 3];
arr.push(10);
console.log(arr);

Question 6

const arr = [1, 2, 3, 4];
arr.splice(1, 1);
console.log(arr);

Question 7

const arr = [1, 2, 3, 4, 5];
arr.pop();
console.log(arr);

const arr = [1, 2, 3, 4, 5];
arr.splice(arr.length - 1, 1);
console.log(arr);

Question 8

const arr = [1, 2, 3, 4, 5];
if (arr.includes(3)) {
  console.log("yes");
} else {
  console.log("no");
}

Question 9

const arr = [10, 2, 9, 41, 35];
arr.sort(sortFn);

function sortFn(num1, num2) {
  return num1 - num2;
}
console.log(arr);

Question 10

const arr = [10, 2, 9, 41, 35];
arr.sort(sortFn);
function sortFn(num1, num2) {
  return num2 - num1;
}
console.log(arr);

Question 11

const arr = [10, 2, 9, 41, 35];
const arr2 = [9, 45, 234, 56];
console.log(arr.concat(arr2));
console.log(arr2.concat(arr));

Question 12

const arr = [10, 2, 9];
console.log(arr.toString());

Question 13

const arr = [10, 2, 9, 4];
console.log(arr.reverse());

Question 14

const arr = [10, 2, 9, 4, 5];
let num = 9;
for (let i = 0; i < arr.length; i++) {
  if (arr[i] === num) {
    console.log(i);
  }
}

const arr = [10, 2, 9, 4, 5];
let ans = arr.findIndex(test);
function test(num) {
  return num === 9;
}
console.log(ans);

const arr = [10, 2, 9, 4, 5];
console.log(arr.indexOf(9));

Question 15

const arr = [10, 2, 9, 4, 5, 50];
console.log(arr.slice(0, 3));

Question 16

const arr = [10, 2, 9, 4, 5, 50];
let ans = arr.map(test);
function test(num) {
  return num * 2;
}
console.log(ans);

Question 17

const arr = [10, 2, 9, 4];
let sum = 0;
let index = 0;
while (index < arr.length) {
  sum = sum + arr[index];
  index++;
}
console.log(sum);

Question 18

const arr = [10, 2, 9, 4];
let ans = arr.filter(test);
function test(num) {
  return num % 2 === 0;
}
console.log(ans);

Question 19

const arr = [10, 2, 9, 4];
console.log(arr.join("-"));

Question 20

const arr = [10, 2, 9, 4];
const arr2  = [4,56,234,554];
console.log(arr.concat(arr2));
console.log(arr2.concat(arr));