You are welcome!

Some observations and for future references.

It is very important to have correct name for thread. Currently it reads "How to sum up the elements of an integer using python split/join?" and there are several problems with that: there is no elements in integer as integer is not iterable; integer does not support split/join. Problem is actually about string which looks like integer.

If somebody searches for solution how sum up digits in integer and reaches this thread will be disappointed that despite promising name it's about something else (of course, one can always do str(1234) and use code above).

For those, who looking for "how to sum up digits in integer" without converting into string:

1. Only digits which are at display (shallow sum) i.e 149 = 1 + 4 + 9 = 14. This solution relies of Python feature that in

truth value testing zero of any numeric type is false

def sum_digits(i):
total = 0
while i:
total += i % 10
i //= 10
return total

2. Sum integer digits until there is only one digit (deep sum), i.e 149 --> 1 + 4 + 9 = 14 --> 1 + 4 = 5 This relies on math concept of modulo 9 and not any specific Python feature:

def sum_digits(i):
return (i - 1) % 9 + 1

If modulo 9 concept seems foreign one can use shallow sum recursively to have deep sum:

def sum_digits(i):
total = 0
while i:
total += i % 10
i //= 10
if total < 10:
return total
else:
return sum_digits(total)