enumerate() function in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of enumerate with start index

What is the output of this Python code?

Python

items = ['apple', 'banana', 'cherry']
result = list(enumerate(items, start=1))
print(result)

A [(0, 'apple'), (1, 'banana'), (2, 'cherry')]

B [(1, 'apple'), (2, 'banana'), (3, 'cherry')]

C [(1, 'apple'), (1, 'banana'), (1, 'cherry')]

D [(0, 'apple'), (0, 'banana'), (0, 'cherry')]

💡 Hint

Remember that enumerate can start counting from any number you choose.

The enumerate function returns pairs of (index, item). The start=1 argument makes the index start at 1 instead of 0.

❓ Predict Output

intermediate

Using enumerate in a for loop

What will this code print?

Python

colors = ['red', 'green', 'blue']
for i, color in enumerate(colors):
    if i == 2:
        print(color)

A blue

B green

C red

D IndexError

💡 Hint

The loop prints the color when the index is 2.

The enumerate function pairs each color with its index starting at 0. When i is 2, the color is 'blue'.

🧠 Conceptual

advanced

Behavior of enumerate on empty iterable

What is the result of converting enumerate([]) to a list?

A [(1, None)]

B [(0, None)]

C []

D TypeError

💡 Hint

Think about what happens when you enumerate over an empty list.

Enumerate over an empty iterable produces no items, so converting to list results in an empty list.

❓ Predict Output

advanced

Output of enumerate with tuple unpacking

What does this code print?

Python

data = ['a', 'b', 'c']
for index, value in enumerate(data, 5):
    if index == 6:
        print(value)

A a

B IndexError

C c

D b

💡 Hint

The start index is 5, so the first item has index 5.

Enumerate starts counting at 5, so the second item has index 6, which is 'b'.

❓ Predict Output

expert

Effect of modifying list during enumerate

What happens when you run this code?

Python

lst = [10, 20, 30]
for i, val in enumerate(lst):
    if val == 20:
        lst.append(40)
print(len(lst))

A 4

B 3

C RuntimeError

D Infinite loop

💡 Hint

Think about how enumerate works with the list size changing during iteration.

Enumerate uses an iterator over the list. The list grows by one element during iteration, so the loop continues until the new element is processed. The final list length is 4.