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

Posted by Maria Scott
Maria Scott
2,375 Points

Set Math Challenge 1 trouble getting started

Will someone please give me a boost getting started on this? Start with an empty list to store a new list? Do I need to make separate sets of the dictionary keys and values then get the intersection of those? Or is it possible to go directly to the intersection of the keys and values of the COURSES set (which isn't that really a dictionary?)? Thank you!

1 Answer

Jeff Muday
MOD
Jeff Muday
Treehouse Moderator 28,720 Points
Jeff Muday
Jeff Muday
Treehouse Moderator 28,720 Points

The short answer is yes... either way can be used. It is more efficient to use Python's native set operations, but sometimes you need to construct your own set operations, like below.

def construct_intersection(s1, s2):
    """return the intersection of s1 and s2"""
    s3 = set()
    for x in s1:
        for y in s2:
            if x == y:
                s3.add(x)
    return s3

set1 = {'oats','peas','beans'}
set2 = {'lettuce','milk','oats'}

# Python native operational set intersection
print(set1.intersection(set2))

# a manually constructed intersection
print(construct_intersection(set1, set2))

set(['oats'])
set(['oats'])
Kayc M
Kayc M
12,593 Points
Kayc M
Kayc M
12,593 Points

Thanks that was helpful.