What is going on is that a few objects that are often used, in particular the small (how small is small depends on the implementation) integers, are 'preloaded'. When one of these is then referred to, a new object is not created, but the pre-defined object is used. 10 is apparently a preloaded constant in your implementation, 1e10 is not.
As far as I know, only None is _guaranteed_ to be such a preloaded object, so one should not rely on it in implementations. On Wed, Oct 14, 2009 at 12:46 PM, raffaele ponzini <raffaele.ponz...@gmail.com> wrote: > Dear all, > I have a question concerning the output of the id() function. > In particular since is should: > "" > Return the identity of an object. This is guaranteed to be unique among > simultaneously existing objects. (Hint: it's the object's memory address.) > "" > i expect that for two differnt objects it returns two differnt adress in > memory. > > Let's seee a correct case: >>>> a=10 >>>> b=20 >>>> a is b > False >>>> id(a) > 9986060 >>>> id(b) > 9985940 >>>> c=a >>>> c is a > True >>>> id(c) > 9986060 >>>> id(a) > 9986060 > > And now a strange (for me) output: >>>> d=10 #here i'm assingning a integer value to a fresh new variable d >>>> without any kind of link to the variable a >>>> d is a > True >>>> d==a > True >>>> id(a) > 9986060 >>>> id(b) > 9985940 >>>> id(d) > 9986060 >>>> a=1e10 >>>> d=1e10 >>>> d is a > False >>>> id(a) > 11388984 >>>> id(d) > 11388920 >>>> > > -- > lele > -- > http://mail.python.org/mailman/listinfo/python-list > -- André Engels, andreeng...@gmail.com -- http://mail.python.org/mailman/listinfo/python-list
