Sort by last then first
Input
sort_people([('John','Doe',30),('Jane','Doe',25)])
Output
[('Jane', 'Doe', 25), ('John', 'Doe', 30)]
Same last name 'Doe' so sorted by first name ascending.
Full lesson preview
Use sorted with multiple sort criteria
Sort a list of people by last name, then first name, and then age (descending).
Python practice16 minFunctions as Objects (Lambda, Map/Filter)IntermediateLast updated March 20, 2026
Problem statement
Write a function sort_people(people) that accepts a list of 3-tuples (first_name, last_name, age) and returns a new list sorted by: 1) last name (ascending), 2) first name (ascending), and 3) age (descending). Use sorted with a single key function (lambda returning a tuple).
Task
Practice using sorted with a lambda key that returns a tuple to express multiple sort criteria, including reversing a criterion by inverting the value.
Examples
Input format
A Python list of tuples where each tuple is (first_name: str, last_name: str, age: int).
Output format
A new list of tuples sorted according to the described multi-criteria.
Constraints
Do not use multiple sorts in sequence. Use a single sorted(...) call with a lambda key returning a tuple. Do not modify the input list.
Samples
Sample 1
Input
sort_people([('Sam','Smith',20),('Sam','Smith',30)])
Output
[('Sam', 'Smith', 30), ('Sam', 'Smith', 20)]
Same first and last names, so age is used descending.