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

Posted by Josiah Austin Gulden
Josiah Austin Gulden
2,924 Points

most_courses returns wrong value

Tested this code in Workspaces with a sample dictionary and it seems to work, but I'm getting a "Didn't get the right teacher name" error no matter what I try. What am I missing?

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(teachers):
    return int(len(teachers))

def num_courses(teachers):
    course_total = 0
    for teacher in teachers:
        course_total += int(len(teachers[teacher]))
    return course_total

def courses(teachers):
    course_list = []
    for teacher in teachers:
        course_list.extend(teachers[teacher])
    return course_list

def most_courses(teachers):
    max_count = 0
    max_teacher = None
    for teacher in teachers:
        if len(teacher) > max_count:
            max_teacher = teacher
            max_count = len(teacher)
    return max_teacher

2 Answers

Stuart Wright
Stuart Wright
41,119 Points
Stuart Wright
Stuart Wright
41,119 Points

When you loop over a dictionary as you have:

for teacher in teachers:

You are looping over the keys, not the values. So when you check for the length of teacher in your next line, you are checking the length of the key, not the values. To loop over keys and values, you can use:

for teacher, courses in teachers.items():

Now the teacher variable is the current key in the loop, and courses is the current value.

You'll need to change a couple of other things inside the loop as a result, but I'll leave that for you to work out.

Josiah Austin Gulden
Josiah Austin Gulden
2,924 Points
Josiah Austin Gulden
Josiah Austin Gulden
2,924 Points

thanks!