How do I enable 'doctest.ELLIPSIS' at the Python prompt?

Question

I often see examples that use doctest.ELLIPSIS to limit output in interactive examples of Python use,

>>> print range(20) # doctest:+ELLIPSIS
[0, 1, ..., 18, 19]

and see here how to enable the feature in modules; but I can't figure out how to enable this feature interactvely.

How do I enable doctest.ELLIPSIS at the Python or IPython prompt?

Answer 1

It's not limiting the output, it's telling doctest it doesn't need to check all of it. That line of code will still produce the full output:

 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]

But doctest will only check the bits before and after the ....

I don't know of anything to limit the output like that in interactive sessions, though if you use Python 3, you could write your own implementation of print() to do it.