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Kimmo Ojala
Python Web Development Techdegree Student 8,257 PointsKeys and values in dictionary
Don't really know why this doesn't work.
BR, Kimmo
# 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(dictionary):
return len(dictionary)
def num_courses(dictionary):
courses = []
for value in dictionary.values():
courses = courses + value
return len(courses)
def courses(dictionary):
courses = []
for value in dictionary.values():
courses = courses + value
return courses
def most_courses(dictionary):
teacher_w_most_subjects = None
highest_number_of_subjects = 0
for key in dictionary.keys():
value = dictionary[key]
number_of_subjects = len(value)
if number_of_subjects > highest_number_of_subjects:
teacher_w_most_subjects = key
return teacher_w_most_subjects
def stats(dictionary):
inner_list = []
outer_list = []
for key in dictionary.keys():
inner_list.append(key)
inner_list.append(len(dictionary[key])
outer_list.append(inner_list)
return outer_list
4 Answers
Kimmo Ojala
Python Web Development Techdegree Student 8,257 PointsThanks it works now! Fixing the inner_list[] to be inside the loop makes sense, but I don't really understand why I do not (cannot) need to specify dictionary.keys() to get the value of the key as I did in the previous challenge (value = dictionary[key].
How come I get value of the key without specifying dictionary.keys()?
def most_courses(dictionary):
teacher_w_most_subjects = None
highest_number_of_subjects = 0
for key in dictionary.keys():
value = dictionary[key]
number_of_subjects = len(value)
if number_of_subjects > highest_number_of_subjects:
teacher_w_most_subjects = key
return teacher_w_most_subjects
Thomas McDonnell
8,212 PointsHi Kimmo, I don't think there is any need to specify dictionary.keys() if you are looping over them. Also should your inner_list not be inside the for loop itself? My own answer followed the same kind logic check out the amended below.
def stats(dictionary): outer_list = [] for key in dictionary: inner_list = [] inner_list.append(key) inner_list.append(len(dictionary[key])) outer_list.append(inner_list) return outer_list
Thomas McDonnell
8,212 PointsHi Kimmo glad to hear its working for you know. I am still very much a beginner here too so don't take this as fact and do some digging yourself. From my understanding when we use a for loop in a dict we are looping over the keys and not the values. If we wanted to loop over the values we would us a nested loop i.e a for loop within a for loop
like this:
for key in dict: for v in key:
Kimmo Ojala
Python Web Development Techdegree Student 8,257 PointsHi Thomas,
Actually, I realized that there was a syntax error in my code, a missing parenthesis. This code works now:
def stats(dictionary):
outer_list = []
for key in dictionary.keys():
inner_list = []
inner_list.append(key)
inner_list.append(len(dictionary[key]))
outer_list.append(inner_list)
return outer_list
Thanks for pointing out that its's also possible to loop over a dictionary and return values without using the dictionary.keys() method!
BR, Kimmo