Simple Way To Calculate Padding Based On Modulo/remainder

If I have a string of length L=77 that I want to pad to a length that is a multiple of N=10. I am interested in computing just the amount of padding required. This can be easily do

Solution 1:

The modulus of negative L will do it.

pad = -L % N

Solution 2:

Isn't this one enough?

pad = (N - L) % N

Solution 3:

With math.ceil:

from math import ceil

def pad(l, n):
    return n*ceil(l/n) - l

assertpad(59, 10) == 1assertpad(60, 10) == 0assertpad(61, 10) == 9

Solution 4:

I mean couldn't you simply do

pad = N-L if N-L > 0 else 0

Solution 5:

Use the tenary conditional operator:

0 if (L % N) == 0 else N - (L % N)