def covers_all

Task 2 is only slightly different from task 1

In task 1 you checked to see if the intersection of the sets was not empty.

For task 2, what if you did the same thing, but tested if the intersection of the sets was the same as argument set itself?

I'll bet you can get it now without a code spoiler.

Chris, if you apply the hint that I gave Igor 2 months ago, your test might look something like this:

        if topics & COURSES[course] == topics:  # if covered topics is the same as all topics

In the previous video towards the end, he mentions a few methods you should check out from the link in the teacher's notes. One being the issubset() method (keyword sub) which returns True if all items in the set exists in the specified set, otherwise it returns False. There is a issuperset() method as well which will return False in this case so please do reference the provided links to understand the difference and how to implement. I am just starting like everyone else but this code is much cleaner and passes the test. Good luck, everyone! Update ==> Please do check Steven Parker comment below for a more concise if statement using math operators!

def covers_all(arg):
        output = []
        for title, course in COURSES.items():
                #if arg is within the course return True and append title to output
                if arg.issubset(course):
                        output.append(title)
        return(output)

Not sure why this doesn't work, should I be using subset or something like it. I thought I was just testing to see if the topics where in the set COURSES[course].

def covers(topics):
    list_of_courses=[]
    for course in COURSES.keys():
        if topics & COURSES[course]:
            list_of_courses.append(course)
    return list_of_courses 

def covers_all(topics):
    list_of_courses=[]
    for course in COURSES.keys():
        if topics in COURSES[course]: 
            list_of_courses.append(course)
    return list_of_courses

I'd be pulling my hair out over this one if I wasn't already bald!

I'd finally got it if you don't get the 2nd task but understood how to solve the first one then you can understand this one too So, at the first task, you only check if the intersection contains anything because there is only one argument to check that means that if the intersection is not empty function returns a key. For the second task, you also need to check if there two arguments in intersection (if value.intersection(arguments) == arguments)

def covers_all(arguments):
    outputs = []
    for key, value in COURSES.items():
        if value.intersection(arguments) == arguments:
            outputs.append(key)
    return outputs

if value.intersection(arguments) == arguments: outputs.append(key)

Can somebody explain in detail what does this line is exactly doing.It will be great help

def covers_all(arg):
    courses_list = []
    for course, topics in COURSES.items():
        if arg - topics == set():
            courses_list.append(course)
    return courses_list

I found that if there is no output for difference(meaning that a set is fully included in another set) we have set() as output

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): overlap_list = [] for topics, courses in COURSES.items(): for topic in topics_set: if topic in topics_set.intersection(courses): overlap_list.append(topics) return overlap_list

def covers_all(topics_set): overlap_list=[] for topics,courses in COURSES.items(): #if topics_set.intersection(courses) == topics_set: if topics_set.issubset(courses): overlap_list.append(topics) return overlap_list

print(covers({"Python", "Java"})) print(covers_all({"conditions", "input"}))