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

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of sorting a list of tuples by the second element?

Consider the following Python code that sorts a list of tuples by the second item in each tuple.

Python

data = [(3, 4), (1, 2), (5, 1)]
sorted_data = sorted(data, key=lambda x: x[1])
print(sorted_data)

A [(5, 1), (1, 2), (3, 4)]

B [(1, 2), (3, 4), (5, 1)]

C [(3, 4), (1, 2), (5, 1)]

D [(5, 1), (3, 4), (1, 2)]

💡 Hint

Look at the second element of each tuple and sort by that.

The sorted() function sorts the list by the key function, which here returns the second element of each tuple. So the tuples are ordered by 1, 2, then 4.

❓ Predict Output

intermediate

What is the output when sorting a string with sorted()?

What will be printed by this code?

Python

result = sorted('banana')
print(result)

A ['a', 'a', 'a', 'b', 'n', 'n']

B ['b', 'a', 'n', 'a', 'n', 'a']

C ['n', 'n', 'b', 'a', 'a', 'a']

D ['a', 'b', 'n']

💡 Hint

sorted() returns a list of characters sorted alphabetically.

The string 'banana' is split into characters and sorted alphabetically, resulting in three 'a's, one 'b', and two 'n's in order.

❓ Predict Output

advanced

What is the output of sorting a dictionary by its values?

Given this dictionary, what will be the output of the sorted() call?

Python

scores = {'Alice': 88, 'Bob': 75, 'Charlie': 90}
sorted_scores = sorted(scores.items(), key=lambda item: item[1])
print(sorted_scores)

A [('Alice', 88), ('Bob', 75), ('Charlie', 90)]

B [('Bob', 75), ('Charlie', 90), ('Alice', 88)]

C [('Charlie', 90), ('Alice', 88), ('Bob', 75)]

D [('Bob', 75), ('Alice', 88), ('Charlie', 90)]

💡 Hint

The key function sorts by the dictionary values.

sorted() sorts the items by the second element of each tuple (the score), so the order is Bob (75), Alice (88), Charlie (90).

❓ Predict Output

advanced

What is the output of sorting a list with reverse=True?

What will this code print?

Python

numbers = [4, 1, 7, 3]
sorted_numbers = sorted(numbers, reverse=True)
print(sorted_numbers)

A [4, 1, 7, 3]

B [1, 3, 4, 7]

C [7, 4, 3, 1]

D [7, 3, 4, 1]

💡 Hint

reverse=True sorts from largest to smallest.

The sorted() function sorts the list in descending order because reverse=True is set.

🧠 Conceptual

expert

Which option will cause a TypeError when used with sorted()?

Which of these options will cause a TypeError when passed as the key argument to sorted()?

A key=lambda x: x[0]

B key=5

C key=str.lower

D key=lambda x: len(x)

💡 Hint

The key argument must be a function, not a number.

Passing an integer (5) as the key argument causes a TypeError because sorted() expects a callable function for key.