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Python Functional Python The Lambda Lambada Recursion

please help

Finish the prereqs function so that it recursively finds all of the prerequisite course titles in courses (like "Object-Oriented Python" is a prerequisite for "Django Basics"). You should add() the title of the prerequisite to the pres set and then call prereqs again with the child courses.

In the end, return the prereqs set.

courses.py
courses = {'count': 2,
           'title': 'Django Basics',
           'prereqs': [{'count': 3,
                     'title': 'Object-Oriented Python',
                     'prereqs': [{'count': 1,
                               'title': 'Python Collections',
                               'prereqs': [{'count':0,
                                         'title': 'Python Basics',
                                         'prereqs': []}]},
                              {'count': 0,
                               'title': 'Python Basics',
                               'prereqs': []},
                              {'count': 0,
                               'title': 'Setting Up a Local Python Environment',
                               'prereqs': []}]},
                     {'count': 0,
                      'title': 'Flask Basics',
                      'prereqs': []}]}


    def prereqs(data, pres=None):
 pres.add(prereq_course['title'])

1 Answer

The question itself is a bit misleading. It just asks for the prerequisites - so it's not asking to include the top-level courses too ...

def prereqs(data, pres = None):
    pres = pres or set()
    for prereq in data['prereqs']:
        pres.add(prereq['title'])
        prereqs(prereq, pres)
    return pres