Summary  
This chapter explains how to use the add() method to insert single elements into a Python set, noting that each call can only add one item.  

General domain of usage  
Managing a user’s collection of favorite movies.

Du kan også tilføje elementer til et set. Til dette formål findes der en specifik `add()`-metode. Det er vigtigt at bemærke, at du med denne metode kun kan tilføje **ét element** ad gangen. Hvis du for eksempel vil tilføje 4 elementer, skal du derfor bruge denne metode 4 gange. Lad os se et eksempel.

# Creating an empty set
favorite_movies = set()
print("Initial set:", favorite_movies)  # Output - Initial set: set()

# Adding movies to the set
favorite_movies.add("Inception")
favorite_movies.add("Interstellar")
favorite_movies.add("Tenet")
favorite_movies.add("Dunkirk")

print("Updated set:", favorite_movies)  # Output - Updated set: {'Interstellar', 'Dunkirk', 'Inception', 'Tenet'}

Metoden `add()` egner sig bedst til at tilføje **enkeltstående** elementer.

import unittest
import importlib

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_tarantino_movies_is_declared(self):
        import user_code
        _dynamic_test(
            self,
            hasattr(user_code, 'tarantino_movies'),
            "The `tarantino_movies` set is declared.",
            "Expected `tarantino_movies` to be declared."
        )

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

    def test_tarantino_movies_contains_initial_movies(self):
        import user_code
        initial_movies = {
            'Pulp Fiction',
            'Kill Bill: Vol. 1',
            'Kill Bill: Vol. 2',
            'Inglourious Basterds',
            'Django Unchained'
        }
        _dynamic_test(
            self,
            initial_movies.issubset(user_code.tarantino_movies),
            f"The `tarantino_movies` contains the initial movies: {initial_movies}.",
            f"Expected `tarantino_movies` to contain the initial movies: {initial_movies}, but got {user_code.tarantino_movies}."
        )

    def test_tarantino_movies_contains_new_movies(self):
        import user_code
        new_movies = {'Reservoir Dogs', 'Once Upon a Time in Hollywood'}
        _dynamic_test(
            self,
            new_movies.issubset(user_code.tarantino_movies),
            f"The `tarantino_movies` contains the newly added movies: {new_movies}.",
            f"Expected `tarantino_movies` to contain the newly added movies: {new_movies}, but got {user_code.tarantino_movies}."
        )

    def test_add_method_used(self):
        with open('user_code.py', 'r') as file:
            user_code_source = file.read()
        _dynamic_test(
            self,
            user_code_source.count("add") >= 2,
            "The `add()` method is used at least twice to add new movies.",
            "Expected the `add()` method to be used at least twice to add new movies."
        )

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


test_main.py

Udforsk de grundlæggende datastrukturer i programmeringssproget Python, herunder lister, ordbøger, tupler og sæt, og lær hvordan de anvendes effektivt til at løse virkelige programmeringsudfordringer.

Hvad er en liste? En liste er en ordnet samling, der kan ændres. Den tillader også dublerede elementer.

Tilføjelse af Enkelt Element til et Sæt i Python

Løsning