CODEWITHSUNDEEP
pythonfunctionpython-3.xcollections
Maiia S.
Maiia S.

Reputation: 323

Function to create a list of lists

I need to create a function named stats to return a list of lists where the first item in each inner list is the teacher's name and the second item in the number of courses that teacher has. It should return: [["Tom Smith", 6], ["Emma Li", 3]]

Argument is a dictionary that looks like:

teacher_dict = {'Tom Smith': ['a', 'b', 'c', 'd', 'e', 'f'], 'Emma Li': ['x', 'y', 'z']}

Here is my attempt:

def stats(teacher_dict):
    big_list = []
    for teacher, courses in teacher_dict.items():
        number_of_courses = []
            for key in teacher_dict:
            teacher = ''
            num = 0
            for item in teacher_dict[key]:
                num += 1
            number_of_courses.append((key,num))
    return big_list.append([teacher, number_of_courses])

Another attempt:

def stats(teacher_dict):
    big_list = []
    for teacher in teacher_dict.items():
        number_of_courses = len(teacher_dict[teacher])
    return big_list.append([teacher, number_of_courses])

Any help is greatly appreciated! Both scripts have errors, and I am still very junior in Python, but really want to figure this out. Thank you.

Upvotes: 0

Views: 56

Answers (3)

nosklo
nosklo

Reputation: 223122

Your code example is almost good to go, problem is that the return statement ends the function prematurely. Also the append call must be inside the loop:

def stats(teacher_dict):
    big_list = []
    for teacher in teacher_dict.items():
        number_of_courses = len(teacher_dict[teacher])
        big_list.append([teacher, number_of_courses])
    return big_list

Upvotes: 0

BlackVirusScript
BlackVirusScript

Reputation: 36

teacher_dict = {'Tom Smith': ['a', 'b', 'c', 'd', 'e', 'f'], 'Emma Li': ['x', 'y', 'z']}
stats = lambda teacher_dict: [[teacher, len(courses)] for teacher, courses in teacher_dict.items()]
stats(teacher_dict)

Outputs: [['Emma Li', 3], ['Tom Smith', 6]]

Upvotes: 0

Patrick Haugh
Patrick Haugh

Reputation: 61052

Use a list comprehension 

[[k, len(v)] for k, v in teacher_dict.items()]

Upvotes: 2

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