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Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.  # compare the length of values for two keys in a dictionary.

The task ask me to compare the length of values for different keys in a single dictionary, but i couldn't come up with a way to do it, i was thinking using for loops, but for loops override values each loop so it won't able to compare the length of each value. can someone help?

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(teacher_course):
return len(teacher_course)

def num_courses(teacher_course):
#   number_of_courses = sum(map(len, teacher_course.values()))
return sum(map(len, teacher_course.values()))

def courses(teacher_course):
list = []
for courses in teacher_course.values():
for each_course in courses:
list.append(each_course)
return list
``` Hey there. I've posted my test code below, I was having problems with this task and so I started a test environment and this is what I evened up with that worked. I also couldn't find a way to find the maximum length of a value and then correlate that to a specific key... It had me stumped for quite a while. What you can do though is loop through a dictionaries KEYS and correlate those to different sets of VALUES. With the code below and a bit of testing I think that you should be able to come to a solution. =D

Cheers.

""" sample_dict = { 'James': ['Course', 'Table', 'Bird'], 'Kelly': ['Tiller', 'Table'], 'Jill': ['Jumps'], 'Chris': ['Jumps', 'Table', 'Bird'], 'Davis': ['Tiller', 'Hello', 'Brat'] }

max_val = 0 teacher = ""

for k in sample_dict.keys(): print(len(sample_dict[k])) if max_val < len(sample_dict[k]): max_val = len(sample_dict[k]) teacher = k print('\n') print(max_val) print(teacher)

""" Hello,

I wanted to let you know that your code appears correct to my eyes. I have the exact same code and it works.

def courses(arg): single_list = [] for v in arg.values(): for items in v: single_list.append(items) return single_list

It works for me.

I was thinking however that maybe because your list is named list? I would toss it into my python on my desktop and run it with a made up list to see what kind of error or output you're receiving.

Cheers and happy coding. ha yes, task3 works for me, sorry about the confusion, i only post codes for task 1-3, i was not able to write a working code for task4, hence i didn't post any for that matter. if you can give me a hint about task4 that would be great! Ah I see what you mean.

Ok, so you're already on the right track. You can use a for loop to compare the sizes of the value lists by storing one in a variable and then comparing each new iteration against THAT variable.

max_var = 0 for x in in list: if max_var < x: x = max_var

print max_var

This is an example that should get you started in the right direction I think.

Cheers thanks for the reply, i used your method try to figure out a way to do it, but it could not return the right result, here is my code:

def most_courses(teacher_course): for courses in teacher_course.values(): max_var = 0 if len(courses) > max_var: max_var = len(courses) print(max_var)

i think it would try to compare the length of the courses and return the maximum value, but what it did is print random values of the numbers of the course. i don't know where went wrong. and one more thing, once i got the maximum length of the courses how do i call out the related teachers' name? So, you're really close but with the .values() you're looking at and iterating through the values. I posted my complete code earlier but it looks as if it has been deleted... What you must do is iterate through dict[k].

If you run a print(dict[k] for k in dict) it will print the values of each key. This was the AHA! moment for me. If you still can't figure it out, shoot me a PM and I'll provide my code and walk your through it. This one had me stumped for a while. def most_courses(sample_dict): max_val = 0 teacher = "" courses_list = {} for k in sample_dict.keys(): # print(len(sample_dict[k])) if max_val < len(sample_dict[k]): max_val = len(sample_dict[k]) teacher = k courses_list = sample_dict[k] # print(max_val) print(teacher) print(courses_list)

so i followed your code and got a working code, only a final step left to do here i think is to return the output in the form of a dictionary can you help me out here?