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

Jay Reyes
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Jay Reyes
Python Web Development Techdegree Student 15,937 Points
Posted by Jay Reyes
.a{fill-rule:evenodd;}techdegree
Jay Reyes
Python Web Development Techdegree Student 15,937 Points

Challenge 5 of Stats. This is working on my sandbox...

def stats(dic):
    list_of_teachers = []
    num_courses = 0
    for each in dic:
        iter_list = []
        iter_list.append(each)
        for course in dic.values():
            num_courses += len(course)
        iter_list.append(num_courses)
        list_of_teachers.append(iter_list)
    return list_of_teachers

2 Answers

Jeff Muday
MOD
Jeff Muday
Treehouse Moderator 28,716 Points
Jeff Muday
Jeff Muday
Treehouse Moderator 28,716 Points

Your approach is pretty good, but has problems with how it counts courses for each teacher. The inner loop is basically counting all the courses and then accumulating this in num_courses.

You can fix it like this:

def stats(dic):
    list_of_teachers = []
    num_courses = 0
    for each in dic:
        iter_list = []
        iter_list.append(each)
        courses = dic[each] # get rid of the loop, get the courses based on each (teacher name)
        num_courses = len(courses) # get the length
        iter_list.append(num_courses)
        list_of_teachers.append(iter_list)
    return list_of_teachers

We can simplify it a little using the dic.items() which returns key/value pairs of the name and the courses. Then, it is super easy to append to your list of teachers/courses.

def stats(dic):
    list_of_teachers = []
    for name, courses in dic.items():
        num_courses = len(courses) # number of courses is simply calculated with len
        list_of_teachers.append([name, num_courses])
    return list_of_teachers
Jeff Muday
MOD
Jeff Muday
Treehouse Moderator 28,716 Points
Jeff Muday
Jeff Muday
Treehouse Moderator 28,716 Points

Python is a fun language, there is so much you can do with it!