Group multiple students
Input
group_by_grade([('Alice', 90), ('Bob', 80), ('Charlie', 90)])
Output
{80: ['Bob'], 90: ['Alice', 'Charlie']}
Bob has 80; Alice and Charlie have 90. Names within each grade are sorted; keys are ordered ascending.
Full lesson preview
Group students by grade
Organize a list of (name, grade) pairs into a dictionary mapping each grade to the sorted list of student names.
Python practice19 minDictionaries & SetsIntermediateLast updated March 18, 2026
Problem statement
You are given a list of pairs (name, grade). Build and return a dictionary where each key is a grade and the corresponding value is a list of names of students who have that grade. Each list of names must be sorted alphabetically. To make tests deterministic, construct the final dictionary with its keys in ascending order (so its string representation is predictable).
If the input list is empty, return an empty dictionary.
Task
Given a list of student entries, create a grouped mapping from grade to an alphabetically sorted list of students who have that grade. Ensure the resulting dictionary has keys in sorted order for deterministic representation.
Examples
Input format
A list of tuples (name: str, grade: int).
Output format
A dictionary mapping grade (int) to list of names (list of str).
Constraints
Grades are comparable (ints). Names are strings. The output dictionary must have keys inserted in sorted order for deterministic str representation.
Samples
Sample 1
Input
group_by_grade([('Zoe', 70), ('Ann', 70)])
Output
{70: ['Ann', 'Zoe']}
Both students have grade 70; names sorted alphabetically.