Perplexityy Perplexityy - 5 months ago 8
Python Question

Function is printing multiple times

I've written a function that takes as input a positive integer n and recursively returns a list of factorial values 1!, 2!, . . . , n!.

However, I can't get it to print the list just a single time. I've tried placing the print statement in various loops/locations and it always prints at least 3 times. I've also tried printing the function but it returns 'None', it only seems to print if I have a print statement in the function. Why is this?

Here is my code:

def calc_Factorial(my_list, n, x, e):

if not my_list:
my_list.append(n-(n-1))
calc_Factorial(my_list, n, x, e)
else:
if len(my_list) < n:
my_list.append(my_list[e]*x)
calc_Factorial(my_list, n, x+1, e+1)

if len(my_list) == n:
print(my_list)


e = 0
x = 2
n = int(input('Enter number: '))
my_list = []
calc_Factorial(my_list, n, x, e)

Answer

The value is being printed multiple times because you are using print inside the recursive function. You should return instead of printing inside the recursive function.

def calc_Factorial(my_list, n, x, e):

  if not my_list:
    my_list.append(n-(n-1))
    return calc_Factorial(my_list, n, x, e)
  else:
    if len(my_list) < n:
         my_list.append(my_list[e]*x)
         return calc_Factorial(my_list, n, x+1, e+1)

    if len(my_list) == n:
        return (my_list)


e = 0
x = 2
n = int(input("Enter number: "))
my_list = []
print (calc_Factorial(my_list, n, x, e))
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