Instruction
Very well done! There are two more functions that create a new set from a relationship. One of them is difference():
kate_fav_movies = {'Halloween', 'A Star Is Born', 'Hocus Pocus'}
alan_fav_movies = {'A Star Is Born', 'The Lion King', 'Harry Potter'}
kate_unique_movies = kate_fav_movies.difference(alan_fav_movies)
print('Kate has the following movies that Alan doesn\'t have:', kate_unique_movies)
Notice that kate_unique_movies contains all movies from kate_fav_movies that are not present in alan_fav_movies. difference() is not symmetrical – the two lines below yield different results:
kate_fav_movies.difference(alan_fav_movies) alan_fav_movies.difference(kate_fav_movies)
You can see the results for both invocations in the picture below:
Alternatively, you can use the following notation:
kate_fav_movies - alan_fav_movies alan_fav_movies - kate_fav_movies
The symmetric_difference() function returns those elements that are present in either set, but not in both sets. Here is how it works:
The syntax is comparable to that of difference() ...
kate_fav_movies.symmetric_difference(alan_fav_movies)
... and you can also use a slightly different abbreviated form:
kate_fav_movies ^ alan_fav_movies
Exercise
Use the symmetric_difference() function to solve the following problem:
You are again given data for employees in cities A and B; some of these employees work in both cities. Your task is to find all employees that only work in a single location and print the following:
These employees only work in a single location:
1. {name1}
2. {name2}
...
Stuck? Here's a hint!
In your solution, use:
city_a_employees.symmetric_difference(city_b_employees)
