Why does the following behave unexpectedly in Python?
>>> a = 256 >>> b = 256 >>> a is b True # This is an expected result >>> a = 257 >>> b = 257 >>> a is b False # What happened here? Why is this False? >>> 257 is 257 True # Yet the literal numbers compare properly
I am using Python 2.5.2. Trying some different versions of Python, it appears that Python 2.3.3 shows the above behaviour between 99 and 100.
Based on the above, I can hypothesize that Python is internally implemented such that "small" integers are stored in a different way than larger integers and the
is operator can tell the difference. Why the leaky abstraction? What is a better way of comparing two arbitrary objects to see whether they are the same when I don't know in advance whether they are numbers or not?