In [29]: a,b = 1.0,1.0
In [30]: a is b
Out[30]: True
In [31]: a = 1.0
In [32]: b = 1.0
In [33]: a is b
Out[33]: False

# ?!?

this is not a bug.  ask this type of question on comp.lang.python.

in short: 'is' is not an equality comparison operator.  it compares
object instance identity.

Really, "is" is not equality but is object equivalence, wow I did not
know that. So why is the first one true MR. This is truly a bug, why
is the first one optimized while the second one isn't. And how come
integers are allways optimized in that sense. Go close other tickets.

"is" is for testing object identity, not numeric equality.  That "1 is
1" is always true is simply an implementation detail common to all
recent versions of CPython, due to CPython caching "very small" integer
objects.  The language definition neither requires nor forbids this, so
any program relying on it is in error.  Likewise any program relying on
"1.0 is 1.0" being false is also in error.

Atleast you didnt really challenge my inelegence like greg did. If you
look at my small interpreted session, is returned true the first time.
Why is that. The ticket title may not have been perfect, I was trying
to be sarcastic/funny.

I am asking why are objects sometime the same instance while sometimes
aren't for floats.

the only intelligence i'm challenging is that this is not appropriate
for a bug tracker.  bring it up on a users mailing list.

Please take requests for discussion to comp.lang.python.  Many people
there understand this behavior and will be happy to explain it in as
much detail as you want.  The bug tracker is not the place for this.