[Tutor] rounding up to the nearest multiple of 8

[Joel Goldstick]

On Thu, Oct 4, 2012 at 3:47 PM, Albert-Jan Roskam <fomcl at yahoo.com> wrote:
> Hi,
>
> The function below works, but it's such a kludge! Is there a way to make this more elegant?
> As said in the docstring, I want to round up a given integer to the nearest multiple of 8. I was thinking
> of something like math.ceil.
>
> def _getPadding(charlen):
>     """ Helper function to replace null bytes ('\x00') at the end of
>     string values. Rounds up <charlen> to the nearest multiple of 8.
>     Every string value is 8 bytes or a multiple thereof. For example, a
>     5-character string needs a padding of 3 spaces to prevent the
>     null bytes
>     >>> dict([(charlen, _getPadding(charlen)) for charlen in range(1, 40, 7)])
>     {1: 8, 36: 40, 8: 8, 15: 16, 22: 24, 29: 32}
>     >>> s = "I love Python"
>     >>> s.ljust(_getPadding(len(s)))
>     'I love Python   '
>     """
>     i = 0
>     while True:
>         i += 1
>         if (i * 8) > charlen:
>             return (i * 8) % charlen + charlen if charlen > 1 else 8
> if __name__ == "__main__":
>     import doctest
>     doctest.testmod()
>
> Thanks!
>
> Regards,
> Albert-Jan
>
>
>>> my_string = "123"
>>> pad = 8 - len(my_string) % 8
>>> my_string = my_string + " " * pad
>>> my_string
'123     '

-- 
Joel Goldstick