Intricacies of Aliasing

[scidam]

All of these are Python peculiar properties:
Small integers are preallocated in array called small_ints see CPython implementation
It covers interval from -5 to 256.
So, if x=500 and y=500, id(x) == id(y) will return False.
Internal behavior with string is harder to explain. Python preallocates each Python string that contains only ascii-chars and digits (may be some special chars too, i didn't explore this in deep) (see here). So, if you try to do the same with, e.g. abc-1, you will end with False:

x = 'abc-1'
y = 'abc-1'
id(x) == id(y)
# False

This is because these strings contains -.
Finally, each time you are creating a list, a new object is created, even if you try to create an empty list:

x = []
y = []
id(x) == id(y)
#False

Since, -5 to 256 numbers are prealloced objects, you can do some terrible things (using ctypes which allows to get direct access to memory), e.g. let assign to object 5 different value, e.g. 8:

import ctypes
mnt = id(6) - id(5) # the number of bytes per num
ctypes.memmove(id(5), id(8), mnt)  # Try to break Python's mind.... (Don't do this)
5 + 3

Output:
11