CODEWITHSUNDEEP
python-3.xmoving-average
ParaH2
ParaH2

Reputation: 517

Moving average program (Python)

I'm trying to solve a math problem but I would like to make some informatic tests before to understand what happend (and maybe find the solution with my program), my problem is :

Consider the list consisting of the first n natural numbers without zero, ie from 1 to n. We define the transformation "moving average" on the list of n elements by adding the average of all the terms at the end of the list and eliminating the first term at the beginning of the list. For example, if n = 4, we have: (1,2,3,4) -> (2,3,4,2.5) By iterating this process many times, one can observe a phenomenon of standardization and that all elements of the list tend to a common value when the number of iterations tends to + infinity. It asks for the value of n for this limit is 254859658745.

Well, i'm trying to program the function "moving average" like this :

def moving_average(liste,t):
k=0
S=0
m=0
c=0
n=len(liste)
while c<t:
    while k<n:
        S+=int(liste[k])
        k+=1
        m=S/n
    liste.pop(0)
    liste.append(m)
    c+=1        
return m

My program works but don't answer what I want, if I take liste=[1,2,3] (for example) for all t>1 the answer is always the same... but I don't understand why.

Can you help me please ?

Upvotes: 1

Views: 354

Answers (1)

GreenAsJade
GreenAsJade

Reputation: 14685

In the interests of helping you move forwards, here is the first part of an answer. The way to debug this is like this:

def moving_average(liste,t):
    k=0
    S=0
    m=0
    c=0
    n=len(liste)
    while c<t:
        print("At c: ", c)
        k=0
        while k<n:
            print(" At k: ", k) 
            S+=int(liste[k])
            k+=1
            m=S/n
            print("  .. new S", S)
            print("  .. new k", k)
            print("  .. new m", m)

        liste.pop(0)
        liste.append(m)
        print(" liste: ", liste)
        c+=1        
    return m

test_list = [1,2,3]

test_t = 4

print("Result:", moving_average(test_list, test_t))

Then look at each result until you find one that isn't what you expect

Since you know better than I do what you expect at each step, you might find the underlying issue quicker than I can by doing this :)

Update:

One "obvious" reason why it's not working is because you're not resetting k each time around the c loop.

If you look at the output before fixing, you will see that the "at K" messages only come out once, the first time through.

I've updated the code above to fix this, and I think it does something like you are expecting. I'm not sure why you are taking taking the int() of liste[k], but that is a separate issue.

Upvotes: 1

Related Questions