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All questions of Arrays in JS for Software Development Exam
What will be the output of the following code?
var arr = [1, 2, 3];
arr.pop();
console.log(arr.length);- a)0
- b)1
- c)2
- d)3
Correct answer is option 'C'. Can you explain this answer?
What will be the output of the following code?
var arr = [1, 2, 3];
arr.pop();
console.log(arr.length);
var arr = [1, 2, 3];
arr.pop();
console.log(arr.length);
a)
0
b)
1
c)
2
d)
3
|
Tanuj Arora answered |
The 'pop()' method removes the last element from the array, reducing its length to 2.
What is the output of the following code snippet?
```javascript
let arr = [1, 2, 3, 4, 5];
let sum = arr.reduce((total, num) => total + num, 0);
console.log(sum);
```- a)0
- b)15
- c)10
- d)6
Correct answer is option 'B'. Can you explain this answer?
What is the output of the following code snippet?
```javascript
let arr = [1, 2, 3, 4, 5];
let sum = arr.reduce((total, num) => total + num, 0);
console.log(sum);
```
```javascript
let arr = [1, 2, 3, 4, 5];
let sum = arr.reduce((total, num) => total + num, 0);
console.log(sum);
```
a)
0
b)
15
c)
10
d)
6
|
Aditi Sen answered |
There is a syntax error in the code snippet. The arrow function in the `reduce` method is incomplete. Please provide the complete code snippet.
What is the output of the following code?
var arr = [1, 2, 3, 4, 5];
arr.forEach(function(element) {
console.log(element * 2);
});- a)2, 4, 6, 8, 10
- b)1, 2, 3, 4, 5
- c)2, 4, 6
- d)1, 4, 9, 16, 25
Correct answer is option 'A'. Can you explain this answer?
What is the output of the following code?
var arr = [1, 2, 3, 4, 5];
arr.forEach(function(element) {
console.log(element * 2);
});
var arr = [1, 2, 3, 4, 5];
arr.forEach(function(element) {
console.log(element * 2);
});
a)
2, 4, 6, 8, 10
b)
1, 2, 3, 4, 5
c)
2, 4, 6
d)
1, 4, 9, 16, 25
|
Maya Mukherjee answered |
Explanation:
forEach method:
- The `forEach` method is used to execute a provided function once for each array element.
- In this code snippet, the `forEach` method is called on the `arr` array.
Function inside forEach:
- The function passed to `forEach` takes an `element` parameter, which represents each element of the array.
- Inside the function, each element is multiplied by 2 using `element * 2`.
- The result of the multiplication is then logged to the console using `console.log`.
Output:
- The output of the code will be the result of multiplying each element of the array by 2.
- So, the output will be: 2, 4, 6, 8, 10.
Therefore, the correct answer is option 'A' - 2, 4, 6, 8, 10.
What is the output of the following code snippet?
```javascript
let arr = [1, 2, 3, 4, 5];
let filteredArr = arr.filter((num) => num % 2 === 0);
console.log(filteredArr);
```- a)[1, 2, 3, 4, 5]
- b)[2, 4]
- c)[1, 3, 5]
- d)[1, 3, 5, 7, 9]
Correct answer is option 'B'. Can you explain this answer?
What is the output of the following code snippet?
```javascript
let arr = [1, 2, 3, 4, 5];
let filteredArr = arr.filter((num) => num % 2 === 0);
console.log(filteredArr);
```
```javascript
let arr = [1, 2, 3, 4, 5];
let filteredArr = arr.filter((num) => num % 2 === 0);
console.log(filteredArr);
```
a)
[1, 2, 3, 4, 5]
b)
[2, 4]
c)
[1, 3, 5]
d)
[1, 3, 5, 7, 9]
|
Diksha Sharma answered |
The 'filter()' method creates a new array with all elements that pass the test implemented by the provided function. In this case, the function filters out the odd numbers from the array.
What is the output of the following code snippet?
let arr = [1, 2, 3, 4, 5];
console.log(arr.join("-"));- a)1,2,3,4,5
- b)12345
- c)1-2-3-4-5
- d)1-2345
Correct answer is option 'C'. Can you explain this answer?
What is the output of the following code snippet?
let arr = [1, 2, 3, 4, 5];
console.log(arr.join("-"));
let arr = [1, 2, 3, 4, 5];
console.log(arr.join("-"));
a)
1,2,3,4,5
b)
12345
c)
1-2-3-4-5
d)
1-2345
|
TeamUnknown answered |
The 'join()' method converts all the elements of an array into a string and concatenates them, using the specified separator (in this case, "-").
Which of the following methods can be used to add elements to the end of an array in JavaScript?- a)'push()'
- b)'pop()'
- c)'shift()'
- d)'unshift()'
Correct answer is option 'A'. Can you explain this answer?
Which of the following methods can be used to add elements to the end of an array in JavaScript?
a)
'push()'
b)
'pop()'
c)
'shift()'
d)
'unshift()'
|
|
Palak Shah answered |
push() method in JavaScript
The push() method in JavaScript is used to add one or more elements to the end of an array. It modifies the original array and returns the new length of the array.
How to use push() method:
- To add a single element:
```
let arr = [1, 2, 3];
arr.push(4);
// arr is now [1, 2, 3, 4]
```
- To add multiple elements:
```
let arr = [1, 2, 3];
arr.push(4, 5);
// arr is now [1, 2, 3, 4, 5]
```
Benefits of using push() method:
- It is a simple and straightforward method to add elements to the end of an array.
- It can be used to add one or multiple elements at once, making it versatile.
Example:
```
let arr = [1, 2, 3];
arr.push(4);
console.log(arr); // Output: [1, 2, 3, 4]
```
Using the push() method is a common practice in JavaScript when you need to append elements to an existing array without altering the existing elements' positions.
What is the output of the following code snippet?
let arr = [1, 2, 3, 4, 5];
console.log(arr.slice(1, 3));- a)[2, 3]
- b)[1, 2]
- c)[3, 4]
- d)[2, 4]
Correct answer is option 'A'. Can you explain this answer?
What is the output of the following code snippet?
let arr = [1, 2, 3, 4, 5];
console.log(arr.slice(1, 3));
let arr = [1, 2, 3, 4, 5];
console.log(arr.slice(1, 3));
a)
[2, 3]
b)
[1, 2]
c)
[3, 4]
d)
[2, 4]
|
KnowIT answered |
The 'slice()' method returns a new array containing the elements from index 1 (inclusive) to index 3 (exclusive). In this case, it returns [2, 3].
What will be the output of the following code?
var arr = [1, 2, 3];
arr.unshift(0);
console.log(arr);- a)[0, 1, 2, 3]
- b)[1, 2, 3]
- c)[0, 2, 3]
- d)[0, 1, 3]
Correct answer is option 'A'. Can you explain this answer?
What will be the output of the following code?
var arr = [1, 2, 3];
arr.unshift(0);
console.log(arr);
var arr = [1, 2, 3];
arr.unshift(0);
console.log(arr);
a)
[0, 1, 2, 3]
b)
[1, 2, 3]
c)
[0, 2, 3]
d)
[0, 1, 3]
|
Code Nation answered |
The 'unshift()' method adds an element to the beginning of the array, shifting all other elements to higher indexes.
Which of the following best describes an array in JavaScript?- a)A collection of elements with a fixed size
- b)A collection of elements with dynamic size
- c)A single variable that can store multiple values
- d)A data structure used to store key-value pairs
Correct answer is option 'B'. Can you explain this answer?
Which of the following best describes an array in JavaScript?
a)
A collection of elements with a fixed size
b)
A collection of elements with dynamic size
c)
A single variable that can store multiple values
d)
A data structure used to store key-value pairs
|
Vikram Singh Baghel answered |
Arrays in JavaScript are dynamic, meaning their size can change during runtime.
Which of the following methods can be used to determine the number of elements in an array?- a)length()
- b)size()
- c)count()
- d)sizeOf()
Correct answer is option 'A'. Can you explain this answer?
Which of the following methods can be used to determine the number of elements in an array?
a)
length()
b)
size()
c)
count()
d)
sizeOf()
|
Ritesh Kumar Shivhare answered |
The 'length' property can be used to determine the number of elements in an array.
What is the output of the following code snippet?
```javascript
let arr = [1, 2, 3, 4, 5];
let doubledArr = arr.map((num) => num * 2);
console.log(doubledArr);
```- a)[1, 2, 3, 4, 5]
- b)[2, 4, 6, 8, 10]
- c)[2, 4, 6, 8, 10, 12]
- d)[1, 4, 9, 16, 25]
Correct answer is option 'B'. Can you explain this answer?
What is the output of the following code snippet?
```javascript
let arr = [1, 2, 3, 4, 5];
let doubledArr = arr.map((num) => num * 2);
console.log(doubledArr);
```
let arr = [1, 2, 3, 4, 5];
let doubledArr = arr.map((num) => num * 2);
console.log(doubledArr);
```
a)
[1, 2, 3, 4, 5]
b)
[2, 4, 6, 8, 10]
c)
[2, 4, 6, 8, 10, 12]
d)
[1, 4, 9, 16, 25]
|
|
Diksha Sharma answered |
The 'map()' method creates a new array by applying a provided function to each element of the original array. In this case, the function doubles each element of the array.
What is the output of the following code?
var arr = [1, 2, 3, 4, 5];
arr.splice(2, 1);
console.log(arr);- a)[1, 2, 3, 4, 5]
- b)[1, 2, 4, 5]
- c)[1, 2, 3, 5]
- d)[1, 2, 4]
Correct answer is option 'B'. Can you explain this answer?
What is the output of the following code?
var arr = [1, 2, 3, 4, 5];
arr.splice(2, 1);
console.log(arr);
var arr = [1, 2, 3, 4, 5];
arr.splice(2, 1);
console.log(arr);
a)
[1, 2, 3, 4, 5]
b)
[1, 2, 4, 5]
c)
[1, 2, 3, 5]
d)
[1, 2, 4]
|
Tanuja Mishra answered |
The 'splice()' method removes elements from an array, starting from the specified index. In this case, it removes one element at index 2.
What is the output of the following code snippet?
let arr = [1, 2, 3, 4, 5];
console.log(arr.shift());- a)1
- b)5
- c)4
- d)undefined
Correct answer is option 'A'. Can you explain this answer?
What is the output of the following code snippet?
let arr = [1, 2, 3, 4, 5];
console.log(arr.shift());
let arr = [1, 2, 3, 4, 5];
console.log(arr.shift());
a)
1
b)
5
c)
4
d)
undefined
|
Akash Chawla answered |
Code Explanation:
- The given code snippet declares an array named `arr` with the values `[1, 2, 3, 4, 5]`.
- It then uses the `shift()` method on the array `arr` and logs the returned value to the console using `console.log()`.
Output:
The output of the code snippet is `1`.
Explanation:
- The `shift()` method in JavaScript removes the first element from an array and returns that element.
- In this case, the `shift()` method is called on the `arr` array, which contains the values `[1, 2, 3, 4, 5]`.
- So, the first element of the array is `1`.
- The `shift()` method removes `1` from the array and returns it as the result.
- The returned value (`1`) is then logged to the console using `console.log()`.
Therefore, the output of the code snippet is `1`.
- The given code snippet declares an array named `arr` with the values `[1, 2, 3, 4, 5]`.
- It then uses the `shift()` method on the array `arr` and logs the returned value to the console using `console.log()`.
Output:
The output of the code snippet is `1`.
Explanation:
- The `shift()` method in JavaScript removes the first element from an array and returns that element.
- In this case, the `shift()` method is called on the `arr` array, which contains the values `[1, 2, 3, 4, 5]`.
- So, the first element of the array is `1`.
- The `shift()` method removes `1` from the array and returns it as the result.
- The returned value (`1`) is then logged to the console using `console.log()`.
Therefore, the output of the code snippet is `1`.
What is the output of the following code snippet?
```javascript
let arr = [1, 2, 3, 4, 5];
let includes = arr.includes(3);
console.log(includes);
```- a)true
- b)false
- c)undefined
- d)null
Correct answer is option 'A'. Can you explain this answer?
What is the output of the following code snippet?
```javascript
let arr = [1, 2, 3, 4, 5];
let includes = arr.includes(3);
console.log(includes);
```
```javascript
let arr = [1, 2, 3, 4, 5];
let includes = arr.includes(3);
console.log(includes);
```
a)
true
b)
false
c)
undefined
d)
null
|
Tom Tattle answered |
The 'includes()' method checks if a specific element is present in the array. It returns 'true' if the element is found, otherwise 'false'.
What is the output of the following code?
var arr = [1, 2, 3];
console.log(arr.indexOf(3));- a)-1
- b)0
- c)1
- d)2
Correct answer is option 'D'. Can you explain this answer?
What is the output of the following code?
var arr = [1, 2, 3];
console.log(arr.indexOf(3));
var arr = [1, 2, 3];
console.log(arr.indexOf(3));
a)
-1
b)
0
c)
1
d)
2
|
|
Tanuja Mishra answered |
The 'indexOf()' method returns the index of the first occurrence of the specified element in the array. In this case, 3 is at index 2.
What is the output of the following code snippet?
```javascript
let arr = [1, 2, 3, 4, 5];
let index = arr.findIndex((num) => num === 3);
console.log(index);
```- a)1
- b)2
- c)3
- d)-1
Correct answer is option 'B'. Can you explain this answer?
What is the output of the following code snippet?
```javascript
let arr = [1, 2, 3, 4, 5];
let index = arr.findIndex((num) => num === 3);
console.log(index);
```
```javascript
let arr = [1, 2, 3, 4, 5];
let index = arr.findIndex((num) => num === 3);
console.log(index);
```
a)
1
b)
2
c)
3
d)
-1
|
|
Tom Tattle answered |
The 'findIndex()' method returns the index of the first element in the array that satisfies the provided testing function. In this case, it returns the index of the element 3.
What is the output of the following code snippet?
let arr = [1, 2, 3, 4, 5];
console.log(arr.concat([6, 7]));- a)[1, 2, 3, 4, 5]
- b)[1, 2, 3, 4, 5, 6, 7]
- c)[6, 7]
- d)[2, 3, 4, 5, 6, 7]
Correct answer is option 'B'. Can you explain this answer?
What is the output of the following code snippet?
let arr = [1, 2, 3, 4, 5];
console.log(arr.concat([6, 7]));
let arr = [1, 2, 3, 4, 5];
console.log(arr.concat([6, 7]));
a)
[1, 2, 3, 4, 5]
b)
[1, 2, 3, 4, 5, 6, 7]
c)
[6, 7]
d)
[2, 3, 4, 5, 6, 7]
|
|
KnowIT answered |
The 'concat()' method is used to merge two or more arrays. It returns a new array that contains the elements of the original array followed by the elements of the provided arrays.
What will be the output of the following code?
var arr = [1, 2, 3, 4, 5];
console.log(arr[2]);- a)1
- b)2
- c)3
- d)4
Correct answer is option 'C'. Can you explain this answer?
What will be the output of the following code?
var arr = [1, 2, 3, 4, 5];
console.log(arr[2]);
var arr = [1, 2, 3, 4, 5];
console.log(arr[2]);
a)
1
b)
2
c)
3
d)
4
|
|
TeamUnknown answered |
The code 'arr[2]' accesses the element at index 2 of the arr array, which is 3.
What does the 'indexOf()' method in JavaScript return if the element is not found in the array?- a)-1
- b)null
- c)undefined
- d)false
Correct answer is option 'A'. Can you explain this answer?
What does the 'indexOf()' method in JavaScript return if the element is not found in the array?
a)
-1
b)
null
c)
undefined
d)
false
|
Simar Sharma answered |
The 'indexOf()' method returns -1 if the element is not found in the array.
Which of the following methods can be used to remove the last element from an array in JavaScript?- a)push()
- b)pop()
- c)shift()
- d)unshift()
Correct answer is option 'B'. Can you explain this answer?
Which of the following methods can be used to remove the last element from an array in JavaScript?
a)
push()
b)
pop()
c)
shift()
d)
unshift()
|
|
Ritesh Kumar Shivhare answered |
The 'pop()' method is used to remove the last element from an array in JavaScript.
Which of the following methods can be used to add elements to the end of an array in JavaScript?- a)push()
- b)pop()
- c)shift()
- d)unshift()
Correct answer is option 'A'. Can you explain this answer?
Which of the following methods can be used to add elements to the end of an array in JavaScript?
a)
push()
b)
pop()
c)
shift()
d)
unshift()
|
Anil Kumar answered |
The 'push()' method is used to add elements to the end of an array in JavaScript.
Which method is used to create a new array with the results of calling a provided function on every element in the calling array?- a)'reduce()'
- b)'map()'
- c)'filter()'
- d)'forEach()'
Correct answer is option 'B'. Can you explain this answer?
Which method is used to create a new array with the results of calling a provided function on every element in the calling array?
a)
'reduce()'
b)
'map()'
c)
'filter()'
d)
'forEach()'
|
|
KnowIT answered |
The 'map()' method creates a new array with the results of calling a provided function on every element in the calling array.
What will be the output of the following code?
var arr = [1, 2, 3];
arr.push(4);
console.log(arr.length);- a)3
- b)4
- c)5
- d)6
Correct answer is option 'C'. Can you explain this answer?
What will be the output of the following code?
var arr = [1, 2, 3];
arr.push(4);
console.log(arr.length);
var arr = [1, 2, 3];
arr.push(4);
console.log(arr.length);
a)
3
b)
4
c)
5
d)
6
|
|
Tanuj Arora answered |
The 'push()' method adds an element to the end of the array, increasing its length to 5.
What is the index of the first element in an array?- a)-1
- b)0
- c)1
- d)It varies based on the array size
Correct answer is option 'B'. Can you explain this answer?
What is the index of the first element in an array?
a)
-1
b)
0
c)
1
d)
It varies based on the array size
|
|
Anil Kumar answered |
In JavaScript, array indexing starts from 0, so the first element is accessed using index 0.
What is the result of the following code snippet?
let arr = [1, 2, 3, 4, 5];
arr.splice(1, 2);
console.log(arr.length);- a)3
- b)4
- c)5
- d)2
Correct answer is option 'A'. Can you explain this answer?
What is the result of the following code snippet?
let arr = [1, 2, 3, 4, 5];
arr.splice(1, 2);
console.log(arr.length);
let arr = [1, 2, 3, 4, 5];
arr.splice(1, 2);
console.log(arr.length);
a)
3
b)
4
c)
5
d)
2
|
|
KnowIT answered |
The 'splice()' method removes 2 elements starting from the index 1, so the resulting array has 3 elements.
What is the output of the following code snippet?
let arr = [1, 2, 3, 4, 5];
console.log(arr.pop());- a)1
- b)5
- c)4
- d)undefined
Correct answer is option 'B'. Can you explain this answer?
What is the output of the following code snippet?
let arr = [1, 2, 3, 4, 5];
console.log(arr.pop());
let arr = [1, 2, 3, 4, 5];
console.log(arr.pop());
a)
1
b)
5
c)
4
d)
undefined
|
|
KnowIT answered |
The 'pop()' method removes the last element from the array and returns it. In this case, it removes 5 from the array and returns it.
Which of the following methods can be used to remove elements from an array in JavaScript?- a)'splice()'
- b)'slice()'
- c)'concat()'
- d)'join()'
Correct answer is option 'A'. Can you explain this answer?
Which of the following methods can be used to remove elements from an array in JavaScript?
a)
'splice()'
b)
'slice()'
c)
'concat()'
d)
'join()'
|
|
KnowIT answered |
The 'splice()' method can be used to remove elements from an array.
Which of the following methods can be used to remove the first element from an array in JavaScript?- a)push()
- b)pop()
- c)shift()
- d)unshift()
Correct answer is option 'C'. Can you explain this answer?
Which of the following methods can be used to remove the first element from an array in JavaScript?
a)
push()
b)
pop()
c)
shift()
d)
unshift()
|
|
Tanuja Mishra answered |
The 'shift()' method can be used to remove the first element from an array in JavaScript.
What will be the output of the following code?
var arr = [1, 2, 3, 4, 5];
console.log(arr.length);- a)4
- b)5
- c)6
- d)0
Correct answer is option 'B'. Can you explain this answer?
What will be the output of the following code?
var arr = [1, 2, 3, 4, 5];
console.log(arr.length);
var arr = [1, 2, 3, 4, 5];
console.log(arr.length);
a)
4
b)
5
c)
6
d)
0
|
|
TeamUnknown answered |
The 'length' property returns the number of elements in the array, which is 5 in this case.
What is the output of the following code?
var arr = [1, 2, 3, 4, 5];
var newArr = arr.slice(2);
console.log(newArr);- a)[1, 2]
- b)[1, 2, 3, 4]
- c)[3, 4, 5]
- d)[2, 3, 4, 5]
Correct answer is option 'C'. Can you explain this answer?
What is the output of the following code?
var arr = [1, 2, 3, 4, 5];
var newArr = arr.slice(2);
console.log(newArr);
var arr = [1, 2, 3, 4, 5];
var newArr = arr.slice(2);
console.log(newArr);
a)
[1, 2]
b)
[1, 2, 3, 4]
c)
[3, 4, 5]
d)
[2, 3, 4, 5]
|
|
Tanuja Mishra answered |
The 'slice()' method returns a new array containing elements starting from the specified index. In this case, it starts at index 2.
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