Python – Why does it prints "none"?

Question

i = 1
input_number = int(input("Input a digit you wish to count: "))


def count(n):
    global i
    n = int(n/10)
    if n > 0:
        i = i+1
        count(n)
    else:
        j = i
        print(f"j={j}")
        return j


j = count(input_number)
print(f"i={i}")
print(j)

I’m trying to use a recursive way to print the digits of a number. I used a global counter to count, and can print the global counter as result. However, my question is – why can’t I make the function to return the counter and print the function result directly? It returns None somehow.

Asked By: herohaha

||

Source

Answer 1

The count function does not always return a value, so in those cases, it returns None.

If n is greater than 0, no return is encountered.

   if n > 0:
       i = i+1
       count(n)

You were likely wanting:

    if n > 0:
        i = i+1
        return count(n)

Please also note that if you want integer division, you can use //. E.g. n = int(n/10) can be n = n // 10 or just n //= 10.

Answered By: Chris

Python – Why does it prints "none"?

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