Classes and loops
Related code
class Student:
"""Represents a student.
attributes: name, grade
"""
class University:
"""Represents a university.
attributes: name, students
"""
def print_student(st):
print(f"Name: {st.name}, Grade: {st.grade}")
hp = University()
hp.name, hp.students = "Hasan Prishtina", []
In real-world programs, we rarely deal with just one object. A zoo has many animals. A school has many students. An app has many users. Loops allow us to create, update, and interact with all those objects efficiently.
add_students takes a university and a list of dictionaries,
it iterates the list, creates students and adds them to university.
def add_students(uni, students):
for student in students:
st = Student()
st.name = student['name']
st.grade = student['grade']
uni.students.append(st)
print_university takes a university, it iterates its students and prints each student detail.
def print_university(uni):
print(uni.name)
print("=========================")
print()
for st in uni.students:
print_student(st)
...
students = [
{"name": "Albert Krasniqi", "grade": 6},
{"name": "Abetare Krasniqi", "grade": 7},
{"name": "Bahri Berisha", "grade": 6},
]
add_students(hp, students)
print_university(hp)
Hasan Prishtina ========================= Name: Albert Krasniqi, Grade: 6 Name: Abetare Krasniqi, Grade: 7 Name: Bahri Berisha, Grade: 6
Exercises
class Book:
"""Represents a book.
attributes: title: str, author: str
"""
class Library:
"""Represents a library.
attributes: name: str, books: list[Book]
"""
b = Book()
b.title = "Toke e pergjakur"
b.author = "Nazmi Rrahmani"
hs = Library()
hs.name = "Hivzi Sylejmani"
hs.books = []
book_list = [
{"title": "Toke e pergjakur", "author": "Namzmi Rrahmani"},
{"title": "Lugjet e verdha", "author": "Rexhep Hoxha"},
]
Define a function add_books(library: Library, book_list: list[dict]) that creates books from book_list and adds them to the library.
class Player:
"""Represents a player.
attributes: name: str, position: str
"""
class Team:
"""Represents a team.
attributes: name: str, players: list[Player]
"""
Write a function, print_team(team) that prints the name of the team
and all its players' names and positions as follows:
AC Milan Alessandro Nesta - Defender Paolo Maldini - Defender Andriy Shevchenko - Forward
class Item:
"""Represents an item.
attributes: name: str, price: float
class Cart:
"""Represents a cart.
attributes: items: list[Item]
"""
Write a function, total_price(cart: Cart), that returns the sum of prices of all items in cart.
class Player:
"""Represents a player.
attributes: name: str, position: str, goals: int
"""
class Team:
"""Represents a team.
attributes: name: str, players: list[Player], goals: int
"""
Write a function, set_total_goals(team: Team), that sets team's total goals to team's goals attribute.
class Movie:
pass
class User:
pass
movies = [
("Inception", "alice", 9),
("The Shawshank Redemption", "bob", 10),
("The Godfather", "bob", 10),
("Interstellar", "charlie", 8),
("The Shawshank Redemption", "diana", 9),
]
def populate(data):
ratings = []
for mt, usr, rt in data:
m = Movie()
m.title = mt
u = User()
u.name = usr
ratings.append((u, m))
return ratings
ratings = populate(movies)
a = ratings[0][0].name
b = ratings[-1][-1].title
At the end of execution of the above script, what is value of?
| a: | |
| b: |
Exercises
class Library:
"""Represents a library.
attributes: name, books
"""
class Book:
"""Represents a book.
attributes: title, author
"""
b = Book()
b.title = "Toke e pergjakur"
b.author = "Nazmi Rrahmani"
hs = Library()
hs.name = "Hivzi Sylejmani"
hs.books = []
Write a function, print_library(library),
that prints the library name and its books as follows:
Hivzi Sylejmani ======================== Toke e pergjakur - Nazmi Rrahmani Lugjet e verdha - Rexhep Hoxha ...
class Employee:
"""Represents an employee.
attributes: name: str
"""
class Company:
"""Represents a company.
attributes: name: str, employees: list[Employee]
"""
employees_list = ["Emma Johnson", "Liam Martinez", "Sophia Williams"]
Write a function, add_employees(company: Company, employees_list: list[str]), that takes a list of employee names and adds them as Employee instances to the company.
class Player:
"""Represents a player.
attributes: name: str, position: str, goals: int
"""
class Team:
"""Represents a team.
attributes: name: str, players: list[Player]
"""
Write a function, total_goals(team) that returns the sum of goals scored by the whole team.
class Account:
"""Represents a bank account.
attributes: owner: str, balance: float
"""
class Bank:
"""Represents a bank.
attributes: name: str, accounts: list[Account], total: float
"""
Write a function, set_total_value(bank: Bank), that sets bank's total value to bank's total attribute.
class Movie:
pass
class User:
pass
movies = [
("Inception", "alice", 9),
("The Shawshank Redemption", "bob", 10),
("The Godfather", "bob", 10),
("Interstellar", "charlie", 8),
("The Shawshank Redemption", "diana", 9),
]
def populate(data):
ratings = []
for mt, usr, rt in data:
m = Movie()
m.title = mt
u = User()
u.name = usr
ratings.append((u, m))
return ratings
ratings = populate(movies)
a = ratings[1][0].name
b = ratings[0][1].title
At the end of execution of the above script, what is value of?
| a: | |
| b: |