Python Forum

Hello,
Does anyone know a way of taking digits of a number, putting into a list, and adding them together quicker than this?

while x>0:
        t.append(x%10)
        l+=x%10
        x=(x-x%10)//10

In which 'l' is the sum, and x is the number.

I don't know if it's faster, but you could convert it to a string, read the digits, then convert those back to integers. This gets a list where element 0 is the MSD.

>>> x=5238
>>> l = [int(d) for d in str(x)]
>>> l
[5, 2, 3, 8]

For the math method, divmod would let you use fewer operations. This list is the same as your solution where element 0 is the LSD.

>>> x
5238
>>> l = []
>>> while x:
...   x, remainder = divmod(x, 10)
...   l.append(remainder)
...
>>> l
[8, 3, 2, 5]

If the objective is to get reversed integer then instead of list one can use integer right away:

>>> num = 5238
>>> reversed_num = 0
>>> while num:
...     num, reminder = divmod(num, 10)
...     reversed_num = reversed_num * 10 + reminder
...
>>> reversed_num
8325