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

Python Python Collections (2016, retired 2019) Dictionaries Teacher Stats

Mikkel Bielefeldt
Mikkel Bielefeldt
3,227 Points
Posted by Mikkel Bielefeldt
Mikkel Bielefeldt
3,227 Points

I don't understand

I don't understand this challenge, I feel like I'm some kinda of close but not, and I just can't seem to think of an answer.

teachers.py 
# The dictionary will look something like:
# {'Andrew Chalkley': ['jQuery Basics', 'Node.js Basics'],
#  'Kenneth Love': ['Python Basics', 'Python Collections']}
#
# Each key will be a Teacher and the value will be a list of courses.
#
# Your code goes below here.

def num_teachers(dic):
    return int(len(dic))

def num_courses(dic):
    result = 0
    for a in dic:
        result += len(dic[a])
    return result

def courses(dic):
    for key in dic:
        dic.pop('key', None)
    return list(dic)

1 Answer

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

I can see you had a plan, but two issues stand out:

  • if you put quotes around a variable name, it's no longer a variable and just a literal string
  • if you pop all the items from the dictionary, there will be nothing left to return

Your previous function might make a good model to work from. Just instead of counting the courses, this time you will accumulate them into a single list.