Welcome to the Treehouse Community
Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.
Looking to learn something new?
Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.
Start your free trial
Daniel Schirmer
4,364 PointsHow to get rid of first item
I've got something that works, except that I need to not include the first item, which is not a pre-requisite.
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()
#if we are in a dict
if 'prereqs' in data:
pres.add(data['title'])
prereqs(data['prereqs'], pres)
#if we are in a list
else:
for course in data:
prereqs(course, pres)
return pres
2 Answers
Kenneth Love
Treehouse Guest TeacherYou're always adding data['title'], so you're always going to get "Django Basics" in there. Since you never need that first one, how can you skip it?
Lewis Cowles
74,902 PointsThere has to be a way to use a comprehension for this lol
Kenneth Love
Treehouse Guest TeacherI'm not sure there is, Lewis Cowles. Maybe with a nested one. Feel free to experiment with it.
Lewis Cowles
74,902 PointsDone, I edited and included the code in this question on the forum
Lewis Cowles
74,902 PointsRight, I found a nice way to handle this using comprehensions, although I'm sure there is a better way to handle
def get_title_and_loop( data, pres ):
pres.add( data.get('title') )
prereqs( data, pres );
def prereqs( data, pres=None ):
pres = pres or set()
[ get_title_and_loop( prereq, pres ) for prereq in data.get('prereqs') ]
return pres
Lewis Cowles
74,902 PointsLewis Cowles
74,902 PointsAlso This Post has a pretty good answer