On Saturday 2011 March 19 08:35, Emmanuel Ruellan wrote: > 2011/3/19 Yaşar Arabacı <yasar11...@gmail.com> > > > >>>a=5 > > >>>b=5 > > >>>a == b > > > > True > > > > >>>a is b > > > > True > > > > My question is, why "a is b" is true. What I expected it to be is that, a > > and b are different things with same value. > > Even stranger: > >>> a = 10**10 > >>> b = 10**10 > >>> a == b > > True > > >>> a is b > > False > > >>> a = 5 > >>> b = 5 > >>> a == b > > True > > >>> a is b > > True > > In the general case, you're right: a and b point to two different objects, > but there is also some kind of optimisation for small numbers, and as a > result when a = 5 and b = 5, both point the same '5' object. > > Emmanuel Ruellan
From http://docs.python.org/c-api/int.html The current implementation keeps an array of integer objects for all integers between -5 and 256, when you create an int in that range you actually just get back a reference to the existing object. -- I have seen the future and I am not in it. _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
