lenskit.splitting.SampleFrac
============================

.. py:class:: lenskit.splitting.SampleFrac(frac, rng = None)
   :canonical: lenskit.splitting._holdout.SampleFrac

   Bases: :py:obj:`HoldoutMethod`


   Randomly select a fraction of test rows per user/item.

   :Stability: Caller

   :param frac: The fraction items to select for testing.
   :param rng: The random number generator or seed (see :ref:`rng`).


   .. py:attribute:: fraction
      :type:  float


   .. py:attribute:: rng
      :type:  numpy.random.Generator


   .. py:method:: __call__(items)

      Subset an item list (in the uncommon case of item-based holdouts, the
      item list actually holds user IDs).

      :param udf: The item list from which holdout items should be selected.

      :returns: The list of test items.