[Python-ideas] [Python-Dev] (try-except) conditional expression similar to (if-else) conditional (PEP 308)

[Mark Dickinson]

On Thu, Aug 6, 2009 at 4:14 PM, Steven D'Aprano<steve at pearwood.info> wrote:
> By memory, the IEEE standard allows for 254 different NANs.

Did you mean 2**54 here?  For IEEE 754 binary64 format, I count
2**53-2 bit patterns representing NaNs:  2**52 quiet NaNs and
2**52-2 signaling NaNs. (The 11 exponent bits must all be 1s;
the sign bit and the 52 significand bits can be chosen arbitrarily,
except that two bit patterns are reserved for +/-infinity; the top
significand bit determines whether you've got a signaling or
quiet NaN).

</nitpick>

I agree that that particular example isn't particularly compelling,
but I've definitely encountered other cases where I would have
used this construct if it were available.  Not that that necessarily
makes it a good idea.  :-)

Mark