[Tutor] Need a better name for this function

[Richard D. Moores]

On Thu, Dec 17, 2009 at 02:13, Dave Angel <davea at ieee.org> wrote:

> Try the following in Python 3.1:
>
> def increment(floatval, incr=1):
>   #Given a float of "reasonable" size, increment it by smallest amount
>   #  and if incr is -1, then decrement
>   stringval = floatval.hex()
>   mantissa, exponent = stringval.split("p")
>   mantissa = mantissa.replace(".", "")   #ignore the period
>   mantissa = hex(int(mantissa, 16) + incr)
>   newstringval = mantissa[:3] + "." + mantissa[3:] + "p" + exponent
>   newfloatval = float.fromhex(newstringval)
>   #print(floatval, newstringval, newfloatval)
>   return newfloatval
>
>
> You can specify an increment of +1 or -1, but larger values also work just
> as well.  From limited testing, this works for any positive values that
> aren't in the gradual underflow range.
>
> The parsing and reassembly of the mantissa and exponent are pretty sloppy,
> but maybe they are even correct, for the output of the hex() method.
>
> DaveA

Thanks very much Dave. Enlightening.

Dick