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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.
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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.
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.
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]
|
Tejas Ghosh answered |
Output:
The output of the code snippet is [2, 3].
Explanation:
The code snippet is using the slice() method to extract a portion of the array arr starting from index 1 (inclusive) and ending at index 3 (exclusive).
Here are the steps performed by the slice() method:
1. The slice() method creates a new array by copying a portion of the original array.
2. The first argument of the slice() method specifies the starting index from where the portion should be extracted.
3. The second argument specifies the ending index (exclusive) up to which the portion should be extracted.
4. In the given code snippet, arr.slice(1, 3) extracts the elements from index 1 (inclusive) to index 3 (exclusive).
5. The elements at index 1 and index 2 are 2 and 3 respectively.
6. Therefore, the extracted portion of the array is [2, 3].
Visualization:
To better understand the code snippet, let's visualize the array and the portion extracted using the slice() method:
Original Array: [1, 2, 3, 4, 5]
slice(1, 3):
- Start extracting from index 1 (inclusive)
- Stop extracting at index 3 (exclusive)
Extracted Portion: [2, 3]
Summary:
The slice() method is used to extract a portion of an array. In the given code snippet, the portion extracted from the array [1, 2, 3, 4, 5] using slice(1, 3) is [2, 3].
The output of the code snippet is [2, 3].
Explanation:
The code snippet is using the slice() method to extract a portion of the array arr starting from index 1 (inclusive) and ending at index 3 (exclusive).
Here are the steps performed by the slice() method:
1. The slice() method creates a new array by copying a portion of the original array.
2. The first argument of the slice() method specifies the starting index from where the portion should be extracted.
3. The second argument specifies the ending index (exclusive) up to which the portion should be extracted.
4. In the given code snippet, arr.slice(1, 3) extracts the elements from index 1 (inclusive) to index 3 (exclusive).
5. The elements at index 1 and index 2 are 2 and 3 respectively.
6. Therefore, the extracted portion of the array is [2, 3].
Visualization:
To better understand the code snippet, let's visualize the array and the portion extracted using the slice() method:
Original Array: [1, 2, 3, 4, 5]
slice(1, 3):
- Start extracting from index 1 (inclusive)
- Stop extracting at index 3 (exclusive)
Extracted Portion: [2, 3]
Summary:
The slice() method is used to extract a portion of an array. In the given code snippet, the portion extracted from the array [1, 2, 3, 4, 5] using slice(1, 3) is [2, 3].
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?
```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]
|
Devika Saha answered |
Explanation:
1. Initial Array:
- The initial array `arr` is `[1, 2, 3, 4, 5]`.
2. Mapping Function:
- The `map()` function is used to create a new array by applying a function to each element of the original array.
- In this case, the mapping function `(num) => num * 2` multiplies each element of the original array by 2.
3. Applying Mapping Function:
- When the mapping function is applied to each element of the `arr`, we get the following results:
- 1 * 2 = 2
- 2 * 2 = 4
- 3 * 2 = 6
- 4 * 2 = 8
- 5 * 2 = 10
4. Doubled Array:
- The new array `doubledArr` is `[2, 4, 6, 8, 10]` after applying the mapping function.
5. Output:
- The `console.log(doubledArr)` statement prints the doubled array to the console.
Therefore, the output of the given code snippet is option B) [2, 4, 6, 8, 10].
1. Initial Array:
- The initial array `arr` is `[1, 2, 3, 4, 5]`.
2. Mapping Function:
- The `map()` function is used to create a new array by applying a function to each element of the original array.
- In this case, the mapping function `(num) => num * 2` multiplies each element of the original array by 2.
3. Applying Mapping Function:
- When the mapping function is applied to each element of the `arr`, we get the following results:
- 1 * 2 = 2
- 2 * 2 = 4
- 3 * 2 = 6
- 4 * 2 = 8
- 5 * 2 = 10
4. Doubled Array:
- The new array `doubledArr` is `[2, 4, 6, 8, 10]` after applying the mapping function.
5. Output:
- The `console.log(doubledArr)` statement prints the doubled array to the console.
Therefore, the output of the given code snippet is option B) [2, 4, 6, 8, 10].
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
|
KnowIT answered |
The 'shift()' method removes the first element from the array and returns it. In this case, it removes 1 from the array and returns it.
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, "-").
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
|
|
Tanuja Mishra answered |
The 'forEach()' method executes a provided function once for each array element. In this case, it multiplies each element by 2 and logs the result.
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()'
|
Simar Sharma answered |
The 'push()' method is used to add elements to the end of an array.
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]
|
Ishan Verma answered |
The code snippet is incomplete and missing the closing parentheses and curly bracket for the filter function. Please provide the complete code so that I can provide an accurate output.
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.
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.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 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.
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.
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 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.
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.
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[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.
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.
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.
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.
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