Computing factorials

[Truman]

Question:
Write a program which can compute the factorial of a given numbers.
The results should be printed in a comma-separated sequence on a single line.

my code:

numb = input("Please add a number: ")
def numb_f(x):
    i = 1
    suma = 1
    while i < int(numb):
        suma =  suma * (i+1)
        i = i + 1
        
print(numb_f(numb))

the output is always "None". Don't know why, please advise.

[j.crater]

If you don't specify a return value in your function, it will return None by default.
First you should store the calculated values, and then you can print it.

[Gribouillis]

The only way for a python function to return a value different from None is to use a return statement.

[Truman]

numb = input("Please add a number: ")
def numb_f(x):
    i = 1
    suma = 1
    while i < int(numb):
        suma =  suma * (i+1)
        i = i + 1
    return suma
        
print(numb_f(numb))

Now it works fine.

I also decided to add condition that checks whether input is a number:

numb = input("Please add a number: ")
if type(numb) == int:
    def numb_f(x):
        i = 1
        suma = 1
        while i < int(numb):
            suma =  suma * (i+1)
            i = i + 1
        return suma
        
    print(numb_f(numb))
else:
    print("Please add number!")

but this time it prints else statemenet all the time. What did I do wrong?

---

I made a modification, placed a function out of if/else statemenet but still receive the same outcome.

numb = input("Please add a number: ")
def numb_f(x):
    i = 1
    suma = 1
    while i < int(numb):
        suma =  suma * (i+1)
        i = i + 1
    return suma
if type(numb) == int:       
    print(numb_f(numb))
else:
    print("Please add number!")

[sparkz_alot]

You haven't defined numb as an integer yet. Which begs the question why are you asking for a string instead of an integer to begin with?

numb = int(input("Please add a number: "))

[Truman]

Thank you. It didn't come to my mind that it's possible to define input as integer.

[DeaD_EyE]

It's not a definition, it's a type conversion. Input is always a string. Using the function int, tries to convert the string into a integer. If the content of the string is not a valid integer, you'll get a ValueError.