Python – Why does python have to generate the full scope to test if it floats in scope?

It’s really fast :

1 in range(100000000000000)

It’s really slow :

1.5 in range(100000000000000)

Why does the full range have to be generated to know that 1.5 is not in range(X) and step has to be an integer?

If we check source code :

Include function:

range_contains(rangeobject *r, PyObject *ob)
{
    if (PyLong_CheckExact(ob) || PyBool_Check(ob))
        return range_contains_long(r, ob);

return (int)_PySequence_IterSearch((PyObject*)r, ob,
                                   PY_ITERSEARCH_CONTAINS);
}

It seems to be checking if the integer or bool value method will be used for checking, and if not, then use PY_ITERSEARCH_CONTAINS.