Implement the most_least_frequent() function so that it outputs: The frequency of the most frequent value in the list. The frequency of the least frequent value in the list

Q&A
#1

Screen Link:
https://app.dataquest.io/m/1013/functions%3A-intermediate-practice-problems/6/most-frequent-and-least-frequent

My Code: 

values = [10, 20, 30, 10, 30, 10] 
# answer to this input: 3, 1

def most_least_frequent(values):
    freq = {}
    
    for number in values:
        if number in freq:
            freq[number] +=1
        else:
            freq[number] = 1
    maximum = 0
    minimum = 1
    for i in freq:
        if freq[i] > maximum:
            maximum = freq[i]
        if  freq[i] <= minimum:
            minimum = freq[i]
    return maximum, minimum

print(most_least_frequent(values))
    
Replace this line with your code

What I expected to happen:
when i run the code It is showing me right output which is (3,1) but it is showing me an error saying

What actually happened:

“Your function returned an incorrect answer. Input: [[‘1’, ‘1’, ‘1’, ‘1’, ‘1’, ‘1’, ‘1’]] Your answer: 7, 1 Expected answer: 7, 7”

can you please help me what is wrong in my code?

Also i did not understand why solution uses the None for Maximum and minimum value.

Here is the solution:

# provided input
values = [10, 20, 30, 10, 30, 10] 
# answer to this input: 3, 1
def most_least_frequent(values):
    # 1. compute the frequencies
    freq = {}
    for v in values:
        if v in freq:
            freq[v] += 1
        else:
            freq[v] = 1
    # 2. compute the minimum and maximum
    max_freq = None                             **I don't understand why to use None instead of 0**
    min_freq = None
    for v in freq:
        if max_freq is None or freq[v] > max_freq:    
            max_freq = freq[v]
        if min_freq is None or freq[v] < min_freq:
            min_freq = freq[v]
    return max_freq, min_freq

print(most_least_frequent(values))
#2

Take your code above with freq as {1: 7} and then for each iteration of the loop, write down how the minimum and maximum values change for each step of the iteration and then add print statements to check what happens as well as the loop run. Do you notice why starting with 1 or 0 could be an issue?

Let me know if you notice the problem with your logic for that input and/or if you have further questions.