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

the use of the items() method on part 4

I dont saw it covered on the video i saw alot of answers usuing this method:

def most_courses(teachers_info):
    max_count = 0
    for teacher, courses in teachers_info.items():
        if len(courses) > max_count:
            max_count = len(courses)
            max_teacher = teacher
    return max_teacher

Anyone can explain the items() method to me?

what this line means?

  for teacher, courses in teachers_info.items():

from where this "teacher" var come from? its not supposed to be "courses in teachers.info.items()?, what this "teacher" stands for?

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 len(teachers)

def num_courses(courses):
    number = []
    for course in courses.values():
        number += course
    return len(number)

def courses(num_courses):
    list_courses = []
    for x in num_courses.values():
        list_courses.extend(x)
    return list_courses

def most_courses(teachers_info):
    max_count = 0
    for teacher, courses in teachers_info.items():
        if len(courses) > max_count:
            max_count = len(courses)
            max_teacher = teacher
    return max_teacher

1 Answer

Steven Parker
Steven Parker
231,275 Points

The "items" method allows you to get the key and value at the same time as you iterate a dictionary. So in this case, "teacher" would hold the teacher's name (the key), and "courses" would hold the list of courses associated with that teacher.

For more information, see the chapter on Looping Techniques in the Python documentation.