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

Serge Kovalenko
Serge Kovalenko
9,526 Points
Posted by Serge Kovalenko
Serge Kovalenko
9,526 Points

Example works perfectly on my machine but doesn't pass test criteria of the test.

How come this code is not passing treehouse validation tests? What's wrong? Does work very well on my machine.

def covers(*topics): common_topics = [] for course in COURSES: if len(set(topics).intersection(COURSES[course])) > 0: common_topics.append(course)

return common_topics
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"}
}

import json

def covers(*topics):
    common_topics = []
    for course in COURSES:
        if len(set(topics).intersection(COURSES[course])) > 0:
            common_topics.append(course)

    return json.dumps(common_topics)

2 Answers

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

:warning: Be careful about testing a challenge in an external REPL or IDE.

If you have misunderstood the challenge, it's also very likely that you will misinterpret the results.

In this case, the challenge did not ask for anything in JSON format. You won't need that library and you can return your list directly.

Also, the challenge says your function should take the incoming set as a single parameter, you won't need the "splat" operator ("*").

Serge Kovalenko
Serge Kovalenko
9,526 Points
Serge Kovalenko
Serge Kovalenko
9,526 Points

Steven,

thank you. I am indeed misunderstood that function required only single parameter, not a list. That was the root of the problem. Json library used to provide an output in a form required by the challenge - {"aaa","bbb"} rather then {'aaa', 'bbb'}