Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Python Python Collections (2016, retired 2019) Sets Set Math

David Luo
David Luo
1,215 Points

Set object: intersecting sets of topics, return course title. Not getting right results, but logically seems to work

Any suggestions? Perhaps don't use a list comprehension?

or is method issubset incorrectly used? how about s & topics == s to achieve the same thing?

    "Python Basics": {"Python", "functions", "variables",
                      "booleans", "integers", "floats",
                      "arrays", "strings", "exceptions",
                      "conditions", "input", "loops"},
    "Java Basics": {"Java", "strings", "variables",
                    "input", "exceptions", "integers",
                    "booleans", "loops"},
    "PHP Basics": {"PHP", "variables", "conditions",
                   "integers", "floats", "strings",
                   "booleans", "HTML"},
    "Ruby Basics": {"Ruby", "strings", "floats",
                    "integers", "conditions",
                    "functions", "input"}}

def covers1(s):
    return [course for course, topics in COURSES.items() if s & topics == s] 

def covers(s):
    return [course for course, topics in COURSES.items() if s.issubset(topics)] 
David Luo
David Luo
1,215 Points

finally figured it out.

apparently I thought s.intersection(topics) is the same as s.issubset(topics)

1 Answer