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

Anthony Lopez
Anthony Lopez
963 Points
Posted by Anthony Lopez
Anthony Lopez
963 Points

Set Math task 1

Can someone help me to understand why my code isn't working?

If it is a subset of the sets with in the dict it should append that key into the list, and return the list at the end.

Doesn't seem to be taking this answer though.

sets.py 
COURSES = {
    "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 covers(param):
    new_list = []
    for item in COURSES:
        if param.issubset(COURSES[item]):
            new_list.append(item)
    return new_list

1 Answer

Alexander Davison
Alexander Davison
65,469 Points
Alexander Davison
Alexander Davison
65,469 Points

The param doesn't necessarily have to be a subset of COURSES[item]. Notice that the challenge says:

Have the function return a list of courses from COURSES where the supplied set and the course's value (also a set) overlap.

Therefore just has to have an intersection. Try this instead:

if param.intersection(COURSES[item]) != set():

Other than that, your code is great!

Anthony Lopez
Anthony Lopez
963 Points
Anthony Lopez
Anthony Lopez
963 Points

Thanks Alexander.

So just so I understand, my code should be working?

Alexander Davison
Alexander Davison
65,469 Points

If you copy-and-paste your code into the code challenge, it doesn't work. It isn't supposed to work.

If you pass in a set that is not completely a subset of a topic, but still has a couple items in common, it should still be part of the returned result.

Anthony Lopez
Anthony Lopez
963 Points
Anthony Lopez
Anthony Lopez
963 Points

That answer is purely mine. No copy paste. That's why I'm a bit confused. When I used the ide it returned an empty list as well. Something in that code isn't working I'm just not sure why.

Also what is the purpose of comparing the intersection of the sets with set()?

Your code worked thanks.

Alexander Davison
Alexander Davison
65,469 Points

The != set() bit checks if the intersection is an empty set. Basically, its checking whether or not there is an intersection or not.