Question

Could someone please tell me what corrections I should make to this code. (Python)

Here are the instructions.

• Modify the program so it contains four columns: name, year, price and rating (G,PG,R…)
• Enhance the program so it provides a find by rating function that lists all of the movies that have a specified rating

I can't get the find function to work and I have no idea how to even go about it. For example, when type in 'find' and I enter the rating, I'm always getting an error. I need help.

def list(movie_list):
if len(movie_list) == 0:
print("There are no movies in the list.\n")
return
else:
i = 1
for row in movie_list:
print(str(i) + ". " + row[0]+ " (" + str(row[1]) + ")"+","+ "$"+str(row[2])+","+str(row[3]))
i += 1
print()

def add(movie_list):
name = input("Name: ")
year = input("Year: ")
price = int(input("Price:"))#price
rating =input("Rating:")
movie = []
movie.append(name)
movie.append(year)
movie.append(price)#adding price to the movie list
movie.append(rating)#adding rating to the movie list
movie_list.append(movie)
rating_list.append(movie)
print(movie[0] + " was added.\n")   

def delete(movie_list):
number = int(input("Number: "))
if number < 1 or number > len(movie_list):
print("Invalid movie number.\n")
else:
movie = movie_list.pop(number-1)
print(movie[0] + " was deleted.\n")
#find by rating function
def find_by_rating(movie_list,rating):
if len(movie_list)==0:
print("Find")
return
else:
movie_list=[]
for i in movie_list:
if i[3]==rating:
movie_list.append(i[0])
if len(1)==0:
print("No movies are present with given rating")
else:
print("Movies:")
for i in movie_list:
print(i)
  
  
def display_menu():
print("COMMAND MENU")
print("list - List all movies")
print("add - Add a movie")
print("del - Delete a movie")
print("find- find movie by rating")
print("exit - Exit program")
print()

def main():
movie_list = [["Matrix",1999,9.75,"R"],
["Under the Tuscan",2003,4.99,"PG"],
["V for Vendetta", 2005,14.99,"R"]]

display_menu()
  
while True:
command = input("Command: ")
if command == "list":
list(movie_list)
elif command == "add":
add(movie_list)
elif command == "del":
delete(movie_list)
elif command == "find": #added find command
rating=input("Enter rating:")#taking the rating
find_by_rating(movie_list,rating)#the call
elif command == "exit":
break
else:
print("Not a valid command. Please try again.\n")
print("Bye!")

if __name__ == "__main__":
main()

Answer 1

Here is the code in python for the given problem.

Some corrections are done to the code provided in the question so that the program works as expected.

Some comments are added to the find() function (asked in the question) for better understanding.

Sample output is added at the end.

Code:

def list_movies(movie_list):
    if len(movie_list) == 0:
        print("There are no movies in the list.\n")
        return
    else:
        i = 1
        for row in movie_list:
            print(str(i) + ". " + row[0]+ " (" + str(row[1]) + ")"+","+ "$"+str(row[2])+","+str(row[3]))
            i += 1
            print()

def add(movie_list):
    name = input("Name: ")
    year = input("Year: ")
    price = float(input("Price:"))#price
    rating =input("Rating:")
    movie = []
    movie.append(name)
    movie.append(year)
    movie.append(price)#adding price to the movie list
    movie.append(rating)#adding rating to the movie list
    movie_list.append(movie)
    print(movie[0] + " was added.\n")   

def delete(movie_list):
    number = int(input("Number: "))
    if number < 1 or number > len(movie_list):
        print("Invalid movie number.\n")
    else:
        movie = movie_list.pop(number-1)
        print(movie[0] + " was deleted.\n")
        
#find by rating function
def find_by_rating(movie_list,rating):
    if len(movie_list)==0:           #checks if movie_list is empty
        print("There are no movies in the list")
        return
    else:
        movie_list_by_rating=[]      #creates a new list
        for i in movie_list:
            if i[3]==rating:      #checks if the current movie rating is equal to the rating passed as parameter
               movie_list_by_rating.append(i[0])    #append movie to movie_list_by_rating list
        if len(movie_list_by_rating)==0:    #checks if movie_list_by_rating is empty   
            print("No movies are present with given rating")
        else:
            print("Movies:")
            for i in movie_list_by_rating:
                print(i)              #prints movies with rating passed as parameter
  
  
def display_menu():
    print("COMMAND MENU")
    print("list - List all movies")
    print("add - Add a movie")
    print("del - Delete a movie")
    print("find- find movie by rating")
    print("exit - Exit program")
    print()

def main():
    movie_list = [["Matrix",1999,9.75,"R"],
            ["Under the Tuscan",2003,4.99,"PG"],
                ["V for Vendetta", 2005,14.99,"R"]]

    display_menu()
  
    while True:
        command = input("Command: ")
        if command == "list":
            list_movies(movie_list)
        elif command == "add":
            add(movie_list)
        elif command == "del":
            delete(movie_list)
        elif command == "find": #added find command
            rating=input("Enter rating:")#taking the rating
            find_by_rating(movie_list,rating)#the call
        elif command == "exit":
            break
        else:
            print("Not a valid command. Please try again.\n")
    print("Bye!")

if __name__ == "__main__":
    main()

Sample output: