From the doc of id(object)
:
Return the “identity” of an object. This is an integer which is guaranteed to be unique and constant for this object during its lifetime. Two objects with non-overlapping lifetimes may have the same id() value.
Since the two ranges inside the id()
calls have non-overlapping lifetimes, their id values may be the same.
The two ranges assigned to variables have overlapping lifetimes so they must have different id values.
Edit:
A look into the C sources shows us builtin_id
:
builtin_id(PyObject *self, PyObject *v)
{
return PyLong_FromVoidPtr(v);
}
and for PyLong_FromVoidPtr
.
PyLong_FromVoidPtr(void *p)
{
#if SIZEOF_VOID_P <= SIZEOF_LONG
return PyLong_FromUnsignedLong((unsigned long)(Py_uintptr_t)p);
#else
#ifndef HAVE_LONG_LONG
# error "PyLong_FromVoidPtr: sizeof(void*) > sizeof(long), but no long long"
#endif
#if SIZEOF_LONG_LONG < SIZEOF_VOID_P
# error "PyLong_FromVoidPtr: sizeof(PY_LONG_LONG) < sizeof(void*)"
#endif
return PyLong_FromUnsignedLongLong((unsigned PY_LONG_LONG)(Py_uintptr_t)p);
#endif /* SIZEOF_VOID_P <= SIZEOF_LONG */
}
So the ID is a memory address.