Dictionary Iteration Challenge 2 of 5

Question

I can't figure out what's wrong with this code. It keeps bringing up a "TypeError". Thanks!

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(dictionary):
    number_of_teachers = len(dictionary)
    return number_of_teachers

def num_courses(dictionary):
    for value in dictionary.values():
        return sum(len(value))

Answer 1 · 2018-06-28T01:34:16Z

June 28, 2018 1:34am

When I copy and paste your code, I get this error:

Traceback (most recent call last):                                                               
  File "teachers.py", line 46, in <module>                                                        
    num_courses(dictionary)                                                                      
  File "teachers.py", line 41, in num_courses                                                     
    return sum(len(value))                                                                       
TypeError: 'int' object is not iterable

It's referring to this in your code:

return sum(len(value))

The error can be resolved by removing "sum." However, there is still the issue of your code is only returning the length of a single pass through the teachers (ie. just Andrew's courses). I think you were trying to solve this with sum, but sum does not retain the total with each time through the loop.

I found this challenge easier by keeping count with an int variable and adding the len to the variable each time through the for loop. It might look something like this:

course_count = 0
for value in dictionary:
    course_count += len(dictionary[value])

Keep in mind, the courses are a list inside a dictionary, that's why you want dictionary[value].

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Ekenedilichukwu Osubor

Ekenedilichukwu Osubor

Dictionary Iteration Challenge 2 of 5

1 Answer

John Goodwin

John Goodwin