When is hash(n) == n in Python?

Question

I\'ve been playing with Python\'s hash function. For small integers, it appears hash(n) == n always. However this does not extend to large numbers:

Answer 1

The implementation for the int type in cpython can be found here.

It just returns the value, except for -1, than it returns -2:

static long
int_hash(PyIntObject *v)
{
    /* XXX If this is changed, you also need to change the way
       Python's long, float and complex types are hashed. */
    long x = v -> ob_ival;
    if (x == -1)
        x = -2;
    return x;
}