PYW.png 13a: Prepping for exam 2

Created: 2025-05-06 di 14:17

1. Friday's exam

  • Dictionaries
  • Object Oriented Programming
  • File handling

2. Individual project

  • Feedback by the end of today.
  • Next week: individual meet-ups 14a and 14b
    • Register for your spot: link

3. Mock exam

4

The following piece of code has 2 main (syntax) errors. Explain below what these errors are and how you would fix them. Do not rewrite the fix code!

5

5-a

Write a function that takes the list of dictionaries and a rating as arguments. It should return a new list with the names of the movies that have a rating higher than the one given as an argument. 

movie_db = [
{"title": "A Boy and His Dog", "year": 1975, "rating": 6.6},
{"title": "Ran", "year": 1975, "rating": 8.3},
{"title": "True Grit", "year": 2010, "rating": 8.0},
{"title": "Scanners", "year": 1981, "rating": 6.7},
{"title": "Barbie", "year": 2023, "rating": 6.8},
{"title": "Anora", "year": 2024, "rating": 8.3},
{"title": "Caddyshack", "year": 1980, "rating": 7.2},
{"title": "Gone With the Wind", "year": 1939, "rating": 8.2}
]

def rating_filter(l, rating):
    lst = []
    for i in l:
        if i["rating"] > rating:
            lst.append(i["title"])
    return lst

print(rating_filter(movie_db,7))

5-b

Write a function that takes the list of dictionaries and a year as arguments. It should return a list with the names of the movies that were released before that year. 


movie_db = [
{"title": "A Boy and His Dog", "year": 1975, "rating": 6.6},
{"title": "Ran", "year": 1975, "rating": 8.3},
{"title": "True Grit", "year": 2010, "rating": 8.0},
{"title": "Scanners", "year": 1981, "rating": 6.7},
{"title": "Barbie", "year": 2023, "rating": 6.8},
{"title": "Anora", "year": 2024, "rating": 8.3},
{"title": "Caddyshack", "year": 1980, "rating": 7.2},
{"title": "Gone With the Wind", "year": 1939, "rating": 8.2}
]

def year_filter(l, year):
    lst = []
    for i in l:
        if i["year"] < year:
            lst.append(i["title"])
    return lst

print(year_filter(movie_db,1990))

5-c

Write a function that consumes the list of movies and a character. It should count how many movies contain the given character in their names (case insensitive!) 


movie_db = [
{"title": "A Boy and His Dog", "year": 1975, "rating": 6.6},
{"title": "Ran", "year": 1975, "rating": 8.3},
{"title": "True Grit", "year": 2010, "rating": 8.0},
{"title": "Scanners", "year": 1981, "rating": 6.7},
{"title": "Barbie", "year": 2023, "rating": 6.8},
{"title": "Anora", "year": 2024, "rating": 8.3},
{"title": "Caddyshack", "year": 1980, "rating": 7.2},
{"title": "Gone With the Wind", "year": 1939, "rating": 8.2}
]

def count_chars(l, char):
    count = 0
    for i in l:
        if char.upper() in i["title"].upper():
            count += 1
    return count

print(count_chars(movie_db,"T"))

6

6-a

Open, read and save the information of the file in a Data Type of your choice. Write this as a function that consumes the name of the file. Briefly justify the data type that you have chosen. 

file_path = "/home/misha/Downloads/netflixfeesubscriprion.txt"

def read_data(file_name):
    with open(file_name, "r") as f:
        # # option manual
        # lst = f.readlines()[8:]
        # option auto
        lines = f.readlines()
        lst = []
        for i in lines:
            if "#" in i:
                continue
            else:
                lst.append(i)

    dict_list = []
    for i in lst:
        dict1 = {}
        split = i.strip("\n").split(",")
        dict1["country"] = split[0]
        dict1["basic"] = split[1]
        dict1["standard"] = split[2]
        dict1["premium"] = split[3]
        dict_list.append(dict1)

    return dict_list


print(read_data(file_path))

6-1

Which country (or countries) have the cheapest premium subscription? 


file_path = "/home/misha/Downloads/netflixfeesubscriprion.txt"

def read_data(file_name):
    with open(file_name, "r") as f:
        # # option manual
        # lst = f.readlines()[8:]
        # option auto
        lines = f.readlines()
        lst = []
        for i in lines:
            if "#" in i:
                continue
            else:
                lst.append(i)

    dict_list = []
    for i in lst:
        dict1 = {}
        split = i.strip("\n").split(",")
        dict1["country"] = split[0]
        dict1["basic"] = split[1]
        dict1["standard"] = split[2]
        dict1["premium"] = split[3]
        dict_list.append(dict1)

    return dict_list

dict = read_data(file_path)

# We have to start somewhere, so we
# can pick the first item of the list.
cheapest_country = dict[0]["country"]
cheapest = dict[0]["premium"]

# Find the cheapest
for i in dict:
    if i["premium"] < cheapest:
        cheapest = i["premium"]
        cheapest_country = i["country"]
print(cheapest_country, cheapest)

# Check if this cheapest price happens
# in multiple countries
for i in dict:
    if i["premium"] == cheapest:
         print(i["country"])

6-2

What is the average price for each subscription across all nations? Print your answer as floating numbers rounded to 1 decimal 

file_path = "/home/misha/Downloads/netflixfeesubscriprion.txt"

def read_data(file_name):
    with open(file_name, "r") as f:
        # # option manual
        # lst = f.readlines()[8:]
        # option auto
        lines = f.readlines()
        lst = []
        for i in lines:
            if "#" in i:
                continue
            else:
                lst.append(i)

    dict_list = []
    for i in lst:
        dict1 = {}
        split = i.strip("\n").split(",")
        dict1["country"] = split[0]
        dict1["basic"] = float(split[1])
        dict1["standard"] = float(split[2])
        dict1["premium"] = float(split[3])
        dict_list.append(dict1)

    return dict_list

dict = read_data(file_path)

sum_basic = 0
sum_standard = 0
sum_premium = 0
count = 0
for i in dict:
    sum_basic += i["basic"]
    sum_standard += i["standard"]
    sum_premium += i["premium"]
    count += 1

for i in [sum_basic, sum_standard, sum_premium]:
    answer = i/count
    print(f"{answer:.1f}")

6-3

Which countries have the largest difference between the premium and basic subscriptions? 

file_path = "/home/misha/Downloads/netflixfeesubscriprion.txt"

def read_data(file_name):
    with open(file_name, "r") as f:
        # # option manual
        # lst = f.readlines()[8:]
        # option auto
        lines = f.readlines()
        lst = []
        for i in lines:
            if "#" in i:
                continue
            else:
                lst.append(i)

    dict_list = []
    for i in lst:
        dict1 = {}
        split = i.strip("\n").split(",")
        dict1["country"] = split[0]
        dict1["basic"] = float(split[1])
        dict1["standard"] = float(split[2])
        dict1["premium"] = float(split[3])
        dict_list.append(dict1)

    return dict_list

dict = read_data(file_path)

# We have to start somewhere, so we
# can pick the first item of the list.
biggest_diff = dict[0]["premium"]-dict[0]["basic"]
biggest_diff_country = dict[0]["country"]

# Find the cheapest
for i in dict:
    diff = i["premium"] - i["basic"]
    if diff > biggest_diff:
        biggest_diff = diff
        biggest_diff_country = i["country"]
print(biggest_diff_country, biggest_diff)

print("-----------")
# Check if this max difference happens
# in multiple countries
for i in dict:
    diff = i["premium"] - i["basic"]
    if diff == biggest_diff:
         print(i["country"])

6-4

For a country of your choice, report the difference (in dollars) between: 1) the basic and standard prices, 2) the standard and the premium prices, and 3) and the basic and the premium prices. Report these three as floating numbers rounded to 1 decimal. 

import random

file_path = "/home/misha/Downloads/netflixfeesubscriprion.txt"

def read_data(file_name):
    with open(file_name, "r") as f:
        # # option manual
        # lst = f.readlines()[8:]
        # option auto
        lines = f.readlines()
        lst = []
        for i in lines:
            if "#" in i:
                continue
            else:
                lst.append(i)

    dict_list = []
    for i in lst:
        dict1 = {}
        split = i.strip("\n").split(",")
        dict1["country"] = split[0]
        dict1["basic"] = float(split[1])
        dict1["standard"] = float(split[2])
        dict1["premium"] = float(split[3])
        dict_list.append(dict1)

    return dict_list

list_dict = read_data(file_path)

# Pick random country
i = random.randint(0,len(list_dict))
dict = list_dict[i]

diff1 = dict["premium"]-dict["basic"]
diff2 = dict["premium"]-dict["standard"]
diff3 = dict["standard"]-dict["basic"]

print(dict["country"])
for i in [diff1, diff2, diff3]:
    print(f"{i:.1f}")

7