Summary  
This chapter explains how to remove elements from Python sets using the `remove()` method, which raises an error if the element is missing, and the `discard()` method, which fails silently when the element isn’t found.

General domain of usage  
Data structure manipulation

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`

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)

import unittest

def _dynamic_test(test_case, condition, success_message, failure_message):
    if condition:
        test_case._testMethodName = success_message
        test_case.assertTrue(True, success_message)
    else:
        test_case._testMethodName = failure_message
        test_case.fail(failure_message)

class TestUserCode(unittest.TestCase):
    def test_marvel_movies_is_declared(self):
        import user_code
        _dynamic_test(
            self,
            hasattr(user_code, 'marvel_movies'),
            "The `marvel_movies` set is declared.",
            "Expected `marvel_movies` to be declared."
        )

    def test_marvel_movies_is_set(self):
        import user_code
        _dynamic_test(
            self,
            isinstance(user_code.marvel_movies, set),
            "The `marvel_movies` is of type `set`.",
            "Expected `marvel_movies` to be of type `set`."
        )

    def test_unwanted_movies_removed(self):
        import user_code
        _dynamic_test(
            self,
            'The Dark Knight' not in user_code.marvel_movies and 'Justice League' not in user_code.marvel_movies,
            "The unwanted movies `The Dark Knight` and `Justice League` are removed from the set.",
            "Expected `The Dark Knight` and `Justice League` to be removed from the set."
        )

    def test_updated_set_contains_correct_values(self):
        import user_code
        expected_movies = {
            'Avengers: Endgame',
            'Black Panther',
            'Iron Man',
            'Spider-Man: No Way Home',
            'Guardians of the Galaxy'
        }
        _dynamic_test(
            self,
            user_code.marvel_movies == expected_movies,
            "The `marvel_movies` set contains the correct updated movies.",
            f"Expected `marvel_movies` to contain {expected_movies}, but got {user_code.marvel_movies}."
        )

if __name__ == '__main__':
    unittest.main()

test_main.py

In this course, you'll get to know the fundamental data structures of the Python programming language. We'll explore utilizing Python's native data structures like lists, dictionaries, tuples, and sets to tackle different challenges.

What is a list? A list is an ordered collection that can be modified. It also allows for duplicate elements.

What is a dictionary? A dictionary is an ordered collection that can be changed, but it doesn't allow duplicate entries. It consists of `key:value` pairs, which are used to optimize its structure.

What is a tuple? A tuple is an ordered collection that cannot be altered. It can have duplicate elements. While it's similar to a list, the values in a tuple can be of any type and are indexed by integers. Although not mandatory, it's common to enclose the values of a tuple in parentheses, making them easier to understand in Python.

What is a set? In Python, a `set` is an unordered collection that is both `iterable` and `mutable`, with no repeated elements. While the order of items in a set isn't fixed, it can include a variety of elements. A key benefit of using sets over lists is their highly efficient method for determining if an element exists within the set.

Using the remove() and discard() Methods

Solution

Awesome!

Using the remove() and discard() Methods

Solution

Awesome!