why do I get this behavior from a while loop?

[Tim Wintle]

On Fri, 2009-11-27 at 17:06 +0100, S. Chris Colbert wrote:
> This seems strange to me, but perhaps I am just missing something:
<snip>
> I would think that second loop should terminate at 9.9, no? 
> 
> I am missing something fundamental?

Floating points variables ...
http://en.wikipedia.org/wiki/Floating_point

0.1 isn't represented internally, so you haven't actually reached 10. -
try comparing that "10." (as it's printed) with 10.0 i.e.
     print (t == 10.)

you'll get False - even though they print the same

Tim