Adding and removing list elements in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this list append and remove code?

Consider the following Python code that adds and removes elements from a list. What will be printed?

Python

fruits = ['apple', 'banana', 'cherry']
fruits.append('date')
fruits.remove('banana')
print(fruits)

A ['apple', 'cherry']

B ['apple', 'banana', 'cherry']

C ['apple', 'cherry', 'date']

D ['apple', 'banana', 'cherry', 'date']

💡 Hint

Remember that append adds to the end and remove deletes the first matching element.

The list starts with three fruits. 'date' is added at the end with append. Then 'banana' is removed. The final list has 'apple', 'cherry', and 'date'.

❓ Predict Output

intermediate

What is the output after popping elements from a list?

Look at this code that pops elements from a list. What will be printed?

Python

numbers = [10, 20, 30, 40]
popped = numbers.pop()
print(popped, numbers)

A 10 [20, 30, 40]

B 30 [10, 20, 40]

C 40 [10, 20, 30, 40]

D 40 [10, 20, 30]

💡 Hint

pop() removes and returns the last item by default.

pop() removes the last element, which is 40, and returns it. The list then has the first three elements left.

❓ Predict Output

advanced

What is the output after inserting and removing by index?

What will this code print after inserting and removing elements by index?

Python

letters = ['a', 'b', 'd']
letters.insert(2, 'c')
removed = letters.pop(1)
print(letters, removed)

A ['a', 'c', 'd'] b

B ['a', 'b', 'c', 'd'] b

C ['a', 'b', 'd'] c

D ['a', 'c', 'd'] c

💡 Hint

insert adds at the given index, pop removes and returns the element at the index.

Insert adds 'c' at index 2, so list becomes ['a', 'b', 'c', 'd']. Then pop(1) removes 'b' at index 1. Final list is ['a', 'c', 'd'], removed is 'b'.

❓ Predict Output

advanced

What error does this code raise when removing a non-existent element?

What error will this code raise?

Python

colors = ['red', 'green', 'blue']
colors.remove('yellow')

A ValueError

B KeyError

C IndexError

D TypeError

💡 Hint

remove() raises an error if the item is not found in the list.

Trying to remove 'yellow' which is not in the list raises a ValueError.

🧠 Conceptual

expert

How many elements are in the list after these operations?

Given this code, how many elements remain in the list after all operations?

Python

items = [1, 2, 3, 4, 5]
items.append(6)
items.pop(0)
items.remove(4)
items.insert(2, 7)

A 7

B 5

C 4

D 6

💡 Hint

Count carefully each add and remove operation.

Start with 5 elements. Append adds one (6 elements). pop(0) removes one (5 elements). remove(4) removes one (4 elements). insert adds one (5 elements). Final count is 5.