I have an animation-related problem. To quickly find number of frames that will loop perfectly within animation sequence, I need to know what round divisions of total number of frames are.

I found a code that finds all round divisors of a number, and it's doing it's job, but I also need to sort it by value.

import math
 
# method to print the divisors
def printDivisors(n) :
     
    # Note that this loop runs till square root
    i = 1
    while i <= math.sqrt(n):
         
        if (n % i == 0) :
             
            # If divisors are equal, print only one
            if (n / i == i) :
                print (i,end=" ")
            else :
                # Otherwise print both
                print (i , int(n/i), end=" ")
        i = i   1
 
# Driver method
frames=int(input("Enter a number of frames you have: "))

print ("The divisors for the number of frames you have: ")
printDivisors(frames)
 
#Original code is contributed by Nikita Tiwari.

To sort results I tried to use list and sort functions, but seems like I don't know what I'm doing, because list seems to be not updated.

import math
buffer_list = []

# method to print the divisors
def printDivisors(n) :
     
    # Note that this loop runs till square root
    i = 1
    while i <= math.sqrt(n):
         
        if (n % i == 0) :
             
            # If divisors are equal, append to list only one
            if (n / i == i) :
                buffer_list.append(i)
            else :
                # Otherwise append to list both
                buffer_list.append(i , int(n/i))
        i = i   1
 
# Driver method
frames=int(input("Enter a number of frames you have: "))

print ("The divisors for the number of frames you have: ")

# Sort and print list
buffer_list.sort()
print (buffer_list)

#Original code is contributed by Nikita Tiwari.

CodePudding user response：

You are forgetting to call the printDivisors function, so no items are being added to your list. The sorting code itself is fine.

I've fixed your code below. I changed printDivisors to calculateDivisors, as it is not actually printing anything. I also fixed the second buffer_list.append call, as append only takes one argument.

import math

buffer_list = []

def calculateDivisors(n):
    i = 1
    while i <= math.sqrt(n):
        if (n % i == 0):
            if (n / i == i):
                buffer_list.append(i)
            else:
                buffer_list.append(n // i)
        i = i   1
 
frames = int(input("Enter a number of frames you have: "))
calculateDivisors(frames)
print("The divisors for the number of frames you have: ")
buffer_list.sort()
print(buffer_list)

CodePudding user response：

• Instead of modifying a global list, return it from your function.
• Instead of a while loop, use a for loop.
• list.append only takes a single argument.
• Instead of int(n / i) use integer division: n // i
• You don't need to sort the list, you already know that i is increasing and n // i is decreasing. You just need to make sure that the latter are reversed.
• I agree with Jack Taylor that you want to change the name of the function.
• I'll add type annotations for clarity.
• You don't need to check for n // i == i every iteration, since it can only happen at the last iteration.

Here is a possible solution:

import math

def divisors(n: int) -> list[int]:
    small_divisors = []
    large_divisors = []
    sqrt_n = int(math.sqrt(n))
    for i in range(1, sqrt_n):
        if n % i == 0:
            small_divisors.append(i)
            large_divisors.append(n // i)
    if n % sqrt_n == 0:
        small_divisors.append(sqrt_n)
    return small_divisors   large_divisors[::-1]

frames = int(input("Enter a number of frames you have: "))

print("The divisors for the number of frames you have:")
print(divisors(frames))