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Python Functional Python The Lambda Lambada Recursion

Matthew Smith
Matthew Smith
3,083 Points
Posted by Matthew Smith
Matthew Smith
3,083 Points

I don't understand how to solve this with map, or reduce

I was able to solve the problem, but not by using map, or reduce. Should I have been able to do it using map, or reduce?

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 = pres or set()
    for pre in data['prereqs']:
        pres.add(pre['title'])
        pres = prereqs(pre, pres)
    return pres

edit (updated, so that the prereq's call has all the variables; pasted an earlier version of my solution)

1 Answer

Steven Parker
Steven Parker
231,236 Points
Steven Parker
Steven Parker
231,236 Points

This is specifically an exercise in using recursion, and your solution is correct.

This challenge doesn't require "map" or "reduce", and neither would be very useful for this task.