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

Emil Hejlesen
Emil Hejlesen
3,014 Points
Posted by Emil Hejlesen
Emil Hejlesen
3,014 Points

sets.py

what should i do i dont understand

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_set):
    output = []
    for course, topics in COURSES.items():
        if topics_set & topics:
            output.append(course)
    return output

def covers_all(topic):
    output = []
    for topics in courses.items():
        if topic & topics:
            output.append(topics)
    return output
Grigorij Schleifer
Grigorij Schleifer
10,365 Points
Grigorij Schleifer
Grigorij Schleifer
10,365 Points

Hi Emil, Oskars suggestion is much nicer compared to mine, but here is a, slightly alternative, approach :smile:

def covers_all(topic):
    output = []
    for course in COURSES:
        # the intersection returns a set of identical elements in topic and COURSES
        # you can use the len() method to compare the lenght of topic and the intersection result
        # if topic has the same length as the intersection result
        # add the course to your output list
        if len(COURSES[course] & topic) == len(topic):
            output.append(course)
    return output

The code uses a slightly different logic, but both should work. It is a good exercise to see different code versions and try to understand them all ...

1 Answer

Oskar Lundberg
Oskar Lundberg
9,534 Points
Oskar Lundberg
Oskar Lundberg
9,534 Points

Hello Emil! I changed your covers_all function so that it works as intended. I have only changed what was needed, I hope this will help you :D

def covers_all(topic):
    output = []
    for course, topics in COURSES.items():
        if topic & topics == topic:
            output.append(course)
    return output