Why Arrays Exist and What Problem They Solve in DSA Python - Test Your Knowledge

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create an array with 5 elements initialized to zero.

DSA Python

arr = [[1]] * 5
print(arr)

Drag options to blanks, or click blank then click option'

A0

BNone

C1

D''

Attempts:

3 left

💡 Hint

Common Mistakes

Using None instead of 0 will create an array of None values.

Using 1 will create an array of ones, not zeros.

The array is created with 5 zeros because 0 is used as the initial value.

2fill in blank

medium

Complete the code to access the third element of the array.

DSA Python

arr = [10, 20, 30, 40, 50]
print(arr[[1]])

Drag options to blanks, or click blank then click option'

A3

B1

C2

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using index 3 will access the fourth element, not the third.

Using index 1 will access the second element.

Array indexing starts at 0, so the third element is at index 2.

3fill in blank

hard

Fix the error in the code to correctly update the second element of the array to 99.

DSA Python

arr = [5, 10, 15]
arr[[1]] = 99
print(arr)

Drag options to blanks, or click blank then click option'

A3

B2

C0

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using index 2 updates the third element, not the second.

Using index 3 causes an index error because the array has only 3 elements.

The second element is at index 1, so arr[1] = 99 updates it correctly.

4fill in blank

hard

Fill both blanks to create an array of squares of numbers from 1 to 5.

DSA Python

squares = [x[1]2 for x in range(1, [2])]
print(squares)

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A**

B6

C*

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Using '*' multiplies but does not square the number in this context.

Using 5 as range end excludes the number 5.

Using '**' for power and '6' as the range end (exclusive) creates squares from 1 to 5.

5fill in blank

hard

Fill both blanks to create a dictionary of numbers and their cubes for numbers greater than 2.

DSA Python

cubes = {x: x{BLANK_2}}3 for x in range(1, 6) if x {{BLANK_2}} 2
print(cubes)

Drag options to blanks, or click blank then click option'

Ax

B**

C>

D{

Attempts:

3 left

💡 Hint

Common Mistakes

Using '(' instead of '{' will cause a syntax error.

Using '*' instead of '**' will multiply but not cube.

Using '<' instead of '>' will filter wrong numbers.

Using '{' to start the dictionary, '**' for power, and '>' to filter numbers greater than 2 creates the correct dictionary.