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1. Which key sorts students by grade from high to low, and then by name from A to Z?

sorted(students, key=lambda s: (-s.grade, s.name))sorted(students, key=lambda s: (s.grade, s.name), reverse=True)sorted(students, key=lambda s: (s.name, -s.grade))sorted(students, key=lambda s: (-s.grade, -s.name))

2. The key lambda v: counts[v] prints [6, 2, 2, 6, 4, 4, 4, 4] for the input [4, 6, 2, 2, 6, 4, 4, 4]. Why are the two 6s not kept together with the 2s?

Counter cannot be used as a key, so the sort leaves the 6s where they areThe dict returned its keys as 6, 2, 4, so the sort used that orderThe 6s and 2s tie on count, and sorted() keeps tied items in input order, with no tie-break on the value itselfPython compares the counts as text, so 6 sorts before 2

3. What does this program print? ``

python
from typing import NamedTuple

class Student(NamedTuple):
    name: str
    grade: int

students = [Student("Mia", 75), Student("Kai", 90), Student("Lee", 75), Student("Noor", 90), Student("Ola", 60)]
print(" ".join(s.name for s in sorted(students, key=lambda s: (-s.grade, s.name))))

``

Ola Lee Mia Kai NoorKai Noor Lee Mia OlaKai Noor Mia Lee OlaNoor Kai Mia Lee Ola

4. What does this program print? ``

python
from collections import Counter

values = [5, 3, 5, 9, 3, 5]
counts = Counter(values)
print(sorted(values, key=lambda v: (-counts[v], v)))

``

[9, 3, 3, 5, 5, 5][3, 3, 5, 5, 5, 9][5, 5, 5, 3, 3, 9][5, 5, 5, 9, 3, 3]

5. What does this program print? ``

python
from collections import Counter

text = "level"
counts = Counter(text)
print(sorted(text, key=lambda c: (-counts[c], c)))

``

['e', 'e', 'l', 'l', 'v']['v', 'e', 'e', 'l', 'l']['l', 'l', 'e', 'e', 'v']['e', 'l', 'e', 'l', 'v']

Multi-key and frequency order