List mutability in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to change the first item of the list to 10.

Python

numbers = [1, 2, 3]
numbers[0] = [1]
print(numbers)

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

Anumbers[1]

B0

C'10'

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes around 10 makes it a string, not an integer.

Trying to assign a value to numbers instead of numbers[0].

Lists are mutable, so you can change an item by assigning a new value to its index. Here, we assign 10 to the first item.

2fill in blank

medium

Complete the code to add the number 4 at the end of the list.

Python

numbers = [1, 2, 3]
numbers.[1](4)
print(numbers)

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Ainsert

Bappend

Cextend

Dadd

Attempts:

3 left

💡 Hint

Common Mistakes

Using insert without specifying the index.

Using extend which expects an iterable, not a single item.

The append method adds a single item to the end of the list.

3fill in blank

hard

Fix the error in the code to change the second item to 20.

Python

numbers = [5, 6, 7]
numbers[[1]] = 20
print(numbers)

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A1

B2

C0

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Using index 2 which is the third item.

Using index 3 which is out of range.

List indexes start at 0, so the second item is at index 1.

4fill in blank

hard

Fill both blanks to create a new list with squares of numbers greater than 2.

Python

numbers = [1, 2, 3, 4, 5]
squares = [x[1]2 for x in numbers if x [2] 2]
print(squares)

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A**

B%

C>

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using % which is modulo, not power.

Using + which adds numbers instead of squaring.

Use ** to square numbers and > to filter numbers greater than 2.

5fill in blank

hard

Fill all three blanks to create a dictionary with uppercase keys and values greater than 3.

Python

numbers = {'a': 1, 'b': 4, 'c': 5}
result = [1]: [2] for [3], v in numbers.items() if v > 3}
print(result)

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Ak.upper()

Bv

Ck

Dv.upper()

Attempts:

3 left

💡 Hint

Common Mistakes

Using v.upper() which is invalid because values are integers.

Using k instead of k.upper() for keys.

Use k.upper() for uppercase keys, v for values, and k as the loop variable for keys.