distinction between float & int

[Ishwor]

hi all,
 can anyone tell me why this distinction? i mean why it returns False
on floats??
>>> a = 1
>>> b = 1
>>> a is b
True
>>> a = 1.1
>>> b = 1.1
>>> a is b
False
>>> 

thanx .
-- 
cheers,
Ishwor Gurung