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Python Python Collections (Retired) Dictionaries Teacher Stats

Frank Sherlotti
PLUS
Frank Sherlotti
Courses Plus Student 1,952 Points
Posted by Frank Sherlotti
Frank Sherlotti
Courses Plus Student 1,952 Points

Teacher stats: Challenge 3 of 4. Need some help please.

Didn't get the expected output. Got ['Andrew Chalkley', ['jQuery Basics', 'Database Foundations', 'Building Social Features in Ruby on Rails', 'Build an Interactive Website']]. ---- This is my error message and it looks to me that I've changed the dictionary that I had into a list. But the problem is that it wants me to change the format of the list and I don't think I've learned that before. Was wondering if that's the problem i'm having, and if it is then could someone please explain to me how to change the formatting on a list, THANKS!

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):
  maxcount = 0
  teacher = ''
  for key, value in a_dict.items():
    teacher_value = len(value)
    if teacher_value > maxcount:
      maxcount = teacher_value
      teacher = key
  return teacher

def num_teachers(a_dict):
  max_count = 0
  for k in a_dict:
    k = max_count
    if k == max_count:
      max_count += 1
  return max_count      

def stats(a_dict):
  teachers = []
  a_dictlist = []
  for key, value in a_dict.items():
    teachers = [key, value]
    a_dictlist.append(teachers)
  return teachers

3 Answers

Vittorio Somaschini
Vittorio Somaschini
33,371 Points
Vittorio Somaschini
Vittorio Somaschini
33,371 Points

Hello Frank.

I see 2 problems in your code:

1) inside the for loop, teachers should be a list with what you called the key, but it should not have the values (courses in our case). Instead it should get and use the number of courses, which happens to be the length of this value variable we are creating.

2) Have a close look at the return statement, you are returning the wrong thing!

I am pretty sure you can easily correct these little errors, if not let me know!

Vittorio

Frank Sherlotti
PLUS
Frank Sherlotti
Courses Plus Student 1,952 Points
Frank Sherlotti
Frank Sherlotti
Courses Plus Student 1,952 Points

I now have this which I think I understood what you were trying to point out to me. I also believe you wanted me to get the length of value which I tried but I don't really know how to write it out properly.

def stats(a_dict):
  a_dictlist = []
  teachers = []
  for key, value in a_dict.items():
    teachers = [key], len(value) 
    a_dictlist.append(teachers)
  return a_dictlist
Vittorio Somaschini
Vittorio Somaschini
33,371 Points
Vittorio Somaschini
Vittorio Somaschini
33,371 Points

You are very very close.

The only thing is that also len(value) needs to be inside the list together with "key"

After that you should be good to go

;)

Frank Sherlotti
PLUS
Frank Sherlotti
Courses Plus Student 1,952 Points
Frank Sherlotti
Frank Sherlotti
Courses Plus Student 1,952 Points

Question: Write a function named courses that takes the dictionary of teachers. It should return a list of all of the courses offered by all of the teachers.

def courses(a_dict):
  courses = []
  classes = []
  for key, value in a_dict.items():
    classes = [len(value)]
    courses.append(classes)
  return courses

Could actually use some help with this as well if your still around. Shouldn't this just be like the last code I wrote and take the length of value(courses) and return it as a list? Or am just misunderstanding the question?

Iain Simmons
Iain Simmons
Treehouse Moderator 32,305 Points

In this case, you want to get the value for each teacher, which will be a list of courses, and then combine them all together and return that.

Note that the returned list should be only one dimension though (so, not a list of lists).