Using the remove() and discard() Methods

Sets in Python allow you to remove elements using the remove() and discard() methods. While both methods remove specific elements, there is a key difference:

remove(): raises a KeyError if the element is not in the set;
discard(): does not raise an error if the element is not found; it simply leaves the set unchanged.

Let's explore these methods using a movie collection theme.

# Attempting to remove movies

movies = {"Inception", "Interstellar", "Tenet", "Dunkirk"}

# Remove specific movies

movies.remove("Dunkirk")

movies.remove("Avatar") # This will raise a `KeyError`


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# Attempting to remove movies
movies = {"Inception", "Interstellar", "Tenet", "Dunkirk"}

# Remove specific movies
movies.remove("Dunkirk")
movies.remove("Avatar")  # This will raise a `KeyError`

Now, let's use the discard() method, which behaves similarly but avoids errors if the specified movie is not in the set.

# Define a set of favorite movies

movies = {"Inception", "Interstellar", "Tenet", "Dunkirk", "Memento"}

# Remove specific movies using discard

movies.discard("Dunkirk")

movies.discard("Memento")

movies.discard("Avatar")

# Print the result

print("Final set:", movies)


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# Define a set of favorite movies
movies = {"Inception", "Interstellar", "Tenet", "Dunkirk", "Memento"}

# Remove specific movies using discard
movies.discard("Dunkirk")
movies.discard("Memento")
movies.discard("Avatar")

# Print the result
print("Final set:", movies)

Task

Swipe to start coding

You are given the set marvel_movies. However, two movies from another studio have accidentally been added to this set.

Remove the movie "The Dark Knight" from the set.
Remove the movie "Justice League" from the set.
Use the discard() or remove() methods to accomplish this task.

Solution

marvel_movies = {

'Avengers: Endgame',

'Black Panther',

'Iron Man',

'The Dark Knight',

'Spider-Man: No Way Home',

'Guardians of the Galaxy',

'Justice League'

}

# Write your code here

marvel_movies.discard('The Dark Knight')

marvel_movies.discard('Justice League')

# Testing

print("Updated set:", marvel_movies)

Everything was clear?

Thanks for your feedback!

Section 4. Chapter 5