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

Dominick Bartenope
Dominick Bartenope
2,092 Points
Posted by Dominick Bartenope
Dominick Bartenope
2,092 Points

Why does this not work?

I feel like I'm looping through the dict correctly but it is not passing. Does the argument have to be defined as the COURSES dictionary value before passing it into the function?

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(topics):
    course_list = []
    for key in COURSES:
        if topics in key:
            course_list.append(key)
    return course_list

2 Answers

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

You don't want to compare the topics with the key itself, but with the list associated with it ("COURSES[key]").

But you also don't want to use the membership operator ("in"), since the topics is also a set and you're looking for overlap, not membership. So this would be a good place to use one of the "set math" operations.