can somebody explain why i should use line number 4 to output thing correctly in detailed manner.

Question

i tried line number 4(2nd part) and found output of my programme to be correct but i dodnot get the right explaination

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(dict):
    count=0
    for key in dict.keys():
        count+=1
    return count

def num_courses(dict):
    list1=[]
    for value in dict.values():
        for course in value:
            list1.append(value)
    return len(list1)

Answer 1 · 2019-01-18T00:44:57Z

January 18, 2019 12:44am

You code works but goes to more effort than needed. Let's look at line by line:

def num_courses(dict):
    list1=[]  # accumulate results, OK
    for value in dict.values():  # for each course_list in teacher courses...
        for course in value:  # for each course in course_list...
            list1.append(value)  # append the course_list to results
    return len(list1)  # count the appended course_lists in the list

So given the input:

{'Andrew Chalkley': ['jQuery Basics', 'Node.js Basics'],
  'Kenneth Love': ['Python Basics', 'Python Collections']}

the returned value would be:

len(list1)
len([['jQuery Basics', 'Node.js Basics'], ['jQuery Basics', 'Node.js Basics'], ['Python Basics', 'Python Collections'], ['Python Basics', 'Python Collections']])
4

Since the course_lists are proper lists, you can remove the inner for loop and use len(value). Set a total = 0 before the loops then use total += len(value). Now you have a result that can be returned directly.

Post back if you have more questions. Good luck!!

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Vashisth Bhatt

Vashisth Bhatt

can somebody explain why i should use line number 4 to output thing correctly in detailed manner.

1 Answer

Chris Freeman

Chris Freeman