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Dolapo Sekoni
Courses Plus Student 1,431 Pointsplease help
please help with this
# 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):
count = 0
for teacher in teachers:
count += 1
return count
def num_courses(teachers):
count = 0
for course in teachers:
count += 1
return count
2 Answers
Jeff Muday
Treehouse Moderator 28,720 PointsAny time you are iterating on a dictionary, you need to use the items(), keys(), or values() methods of the dictionary to work with the "key/value" pairs.
Here's an example I typed in to demonstrate...
Python 3.6.4 (v3.6.4:d48eceb, Dec 19 2017, 06:04:45) [MSC v.1900 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> musical_groups = {'Beatles': ['John','Paul','George','Ringo'],
'Van Halen':['David','Eddie','Alex','Wolfgang','Sammy']}
>>> # count the number of keys (groups)
>>> len(musical_groups.keys())
2
>>> # iterate over the keys (groups) and print out
>>> for group in musical_groups.keys():
... print("group name: ", group)
...
group name: Beatles
group name: Van Halen
>>> # iterate over the values (list of group members) and print out
>>> for members in musical_groups.values():
... print("members: ", members)
...
members: ['John', 'Paul', 'George', 'Ringo']
members: ['David', 'Eddie', 'Alex', 'Wolfgang', 'Sammy']
>>>
>>> # now, iterate on items (which allows us to get both the KEY and the VALUE) and print out
>>> for group, members in musical_groups.items():
... print("group: ",group," members: ",members)
...
group: Beatles members: ['John', 'Paul', 'George', 'Ringo']
group: Van Halen members: ['David', 'Eddie', 'Alex', 'Wolfgang', 'Sammy']
>>>
>>> # we can count the members of a specific group by referencing the value
>>> # note, it will throw an error if you don't supply a valid group
>>> def count_members(group):
... members = musical_groups[group]
... return len(members)
...
>>> count_members('Beatles')
4
>>> count_members('Van Halen')
5
Radovan Valachovic
Python Web Development Techdegree Graduate 20,368 PointsHello Dolapo,
What help you need with the code?
John Lack-Wilson
8,181 PointsJohn Lack-Wilson
8,181 PointsHi Dolapo, thanks for posting your code. Could you be more specific about what you need help with?