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

Dmitry Bruhanov
Dmitry Bruhanov
8,513 Points
Posted by Dmitry Bruhanov
Dmitry Bruhanov
8,513 Points

Python collections - sets

I tried this code in a separate online consile. It returns the required result. However, the challenge keeps returning the Bummer! and Try again! Any ideas what is wrong with my code? What am I missing? Thanks in advance!

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):

    key = None
    for key in COURSES.keys():
        if topics & set(key.split()):
            return [key]

2 Answers

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,094 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,094 Points

You are headed in the right direction.

The phrase set(key.split()) creates a set from the key. This yields the sets {"Python", "Basics"}, {"Java", "Basics"}, etc. These will not properly compare with the submitted topics.

:point_right: Instead, you can compare the value retrieved with the key:

        if topics & COURSES[key]:

The code needs to return a list of all courses that intersect with topics

:point_right: Add a blank list that can be appended to when an intersection is found. Then return that list after the for loop

Post back if you need more help. Good luck!!

Dmitry Bruhanov
Dmitry Bruhanov
8,513 Points
Dmitry Bruhanov
Dmitry Bruhanov
8,513 Points

Thank you, I got it done:

def covers(topics):
    topiclist = []
    for key in COURSES.keys():
        for value in COURSES[key]:
            if value in topics:
                topiclist.append(key)
    return topiclist