courses function in code challenge

Question

The question asks us to write a function called courses that takes a dictionary of teachers and lists of the courses they teach and returns a list of all courses taught by all teachers. I figured I would need to loop through the keys in the dictionary, then loop through the items in each list. However, my answer is returning too many classes (when I tried it without the if statement to check for duplicates, it returned even more classes). Any help would be appreciated.

teachers.py

# The dictionary will be something like:
# {'Jason Seifer': ['Ruby Foundations', 'Ruby on Rails Forms', 'Technology Foundations'],
#  'Kenneth Love': ['Python Basics', 'Python Collections']}
#
# Often, it's a good idea to hold onto a max_count variable.
# Update it when you find a teacher with more classes than
# the current count. Better hold onto the teacher name somewhere
# too!
#
# Your code goes below here.
def most_classes(a_dict):
  teacher = ''
  max_count = 0
  for key in a_dict:
    if len(a_dict[key]) > max_count:
      max_count = len(a_dict[key])
      teacher = key
    else:
      continue
  return teacher

def num_teachers(a_dict):
  count = 0
  for key in a_dict:
    count += 1
  return count

def stats(a_dict):
  a_list = []
  for key in a_dict:
    a_list.append([key, (len(a_dict[key]))])
  return a_list

def courses(a_dict):
  a_list = []
  for key in a_dict:
    for item in key:
      if item not in a_list:
        a_list.append(item)
      else:
        continue
  return a_list

Answer 1 · 2015-02-21T20:15:29Z

February 21, 2015 8:15pm

Hi michaelabendroth,

In your outer for loop you're retrieving each key from the dict which is a teacher's name. You're then iterating over each letter of the teacher's name with your inner for loop which is leading you to incorrect results.

Instead, you should try to get the course list for that teacher with a_dict[key] and add it onto your a_list

You can solve this without a nested for loop.

Answer 2 · 2015-02-21T18:58:48Z

February 21, 2015 6:58pm

Remember that your goal here is to get the key and value pairs for each item in the dictionary.

Once you get the items from the dictionary, you can then unpack them into the variables as you'd expect, like so:

def most_classes(teachers):
  top_teacher = ''
  max_count = 0

  for teacher, classes in teachers.items():
    if len(classes) > max_count:
      top_teacher = teacher
      max_count = len(classes)

  return top_teacher

If you just used for teacher, classes in teachers, you'd get a dict back, but not an iterable list of dict_items like you want to work with.

Answer 3 · 2017-05-30T22:42:56Z

May 30, 2017 10:42pm

def num_teachers(teach_dict): count_teachers = [] for teachers in teach_dict: count_teachers.append(teachers) return (len(count_teachers))

This worked for me!

Answer 4 · 2015-02-23T23:03:23Z

February 23, 2015 11:03pm

Here's what worked for me. If statement not necessary:

def courses(teach_dict):
    my_list = []
    for teachers in teach_dict:
        for courses in teach_dict[teachers]:
            my_list.append(courses)
    return my_list

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courses function in code challenge

4 Answers

Jason Anello

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michaelabendroth

Gavin Ralston

Gavin Ralston

Jason Anello

Jason Anello

Gavin Ralston

Gavin Ralston

michaelabendroth

michaelabendroth

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Prince Vonleh

William Ruiz

William Ruiz