Faculty of Arts & Science
Fall 2024 Quiz 5
CSC 110 Y1F
Question 1. Tabular Data [6 marks]
Here is a sample list similar to the data we saw in the lecture. Each column represents an ID, a civic centre name, the number of marriage licenses issued, and the month and year when they were issued (YYYY, MM, DD).
import datetime
marriage_data = [
[1657, ' ET ' , 80, datetime.date(2011, 1, 1)],
[1658, ' NY ' , 136, datetime.date(2011, 1, 1)],
[1659, ' SC ' , 159, datetime.date(2011, 1, 1)],
[1660, ' TO ' , 367, datetime.date(2011, 1, 1)],
[1662, ' NY ' , 150, datetime.date(2011, 2, 1)],
[1664, ' TO ' , 383, datetime.date(2011, 2, 1)]
]
a) What would the following expressions evaluate to? Write your answers in the space provided below each statement.
>>> len(marriage_data)
>>> marriage_data[5][2]
>>> len(marriage_data[-1])
>>> min([row[2] for row in marriage_data])
b) Fill in a plain English docstring description for the function below, based on the provided function body. The preconditions are provided for you. You do not need to provide any doctests or further preconditions.
def do_something(data: list[list], year: int) -> float:
"""
Preconditions:
- year is a positive integer
- data satisfies all of the properties described in the beginning of this question
"""
counts = [row[2] for row in data if row[3] .year == year]
num_months = len({row[3] .month for row in data if row[3] .year == year})
return sum(counts) / num_months
Question 2. Dataclasses [3 marks]
Recall this dataclass we discussed in lecture:
@dataclass
class MarriageData:
"""A record of the number of marriage licenses issued in a civic centre
in a given month .
Instance Attributes:
- id: a unique identifier for the record
- civic_centre: the name of the civic centre
- num_licenses: the number of licenses issued
- date_issued: the month and year these licenses were issued
"""
id: int
civic_centre: str
num_licenses: int
date_issued: datetime .date
Rewrite the function body from the do_something function from the previous question so that it now deals with a list of MarriageData instances. Fill this in below:
def do_something_v2(data: list[MarriageData], year: int) -> float:
"""
Docstring omitted . The code should do the same thing that it does in Question 1 . """
counts =
num_months =
return sum(counts) / num_months
Question 3. Debugging / Index-Based For Loops [3 marks]
The function below is an incorrect attempt to return True if a string s is a palindrome. Your friend Bob believes the function is correct because he tried calling the function with some string arguments which the code did work correctly for. Answer the questions below.
def is_palindrome(s: str) -> bool:
"""Return whether s is a palindrome .
A palindrome is a string that reads the same backward as forward .
>>> is_palindrome( ' davad ' ) True
>>> is_palindrome( ' david ' )
False """
n = len(s)
for i in range(n // 2):
if s[i] != s[n - 1 - i]:
return False
else:
return True
Part (a) [1 mark]
Give an example of a valid argument for s where this function will return the correct expected value (according to the docstring):
Part (b) [1 mark]
Give an example of a valid argument for s where this function will NOT return the correct expected value:
Part (c) [1 mark]
Briefly explain (in 1–2 sentences) why this function is incorrect (identify the issue in the code):