Sum of Digits in a specific way in Python

Question

I'm looking for a code that runs, i.e:

    int(input) = 2565

Printed Output should be like:

    2 + 5 + 6 + 5  = 18 = 1 + 8 = 9

I wrote the code that gives final answer "9". But I couldn't managed to write it with every digit separated "+" sign. Assuming that I need to use while loop but how can I write the code so it will be like the output above?

Answer 1

You can play around with the end keyword argument of the print function which is the last character/string that print will put after all of its arguments are, well, printed, by default is "\n" but it can be change to your desire.

And the .join method from string which put the given string between the given list/iterable of strings to get the desire result:

>>> " + ".join("123")
'1 + 2 + 3'
>>> 

Mixing it all together:

def sum_digit(n):
    s = sum(map(int,str(n)))
    print(" + ".join(str(n)),"=",s, end="")
    if s<10:
        print()
        return s
    else:
        print(" = ",end="")
        return sum_digit(s)

Here we first get the sum of the digit on s, and print it as desire, with end="" print will not go to the next line which is necessary for the recursive step, then we check if done, and in that case print a new empty line if not we print an additional = to tie it for the next recursive step

>>> sum_digit(2565)
2 + 5 + 6 + 5 = 18 = 1 + 8 = 9
9
>>> 

This can be easily be modify to just return the accumulated string by adding an extra argument or to be iterative but I leave those as exercise for the reader :)