lenskit.metrics.ranking.Hit
===========================

.. py:class:: lenskit.metrics.ranking.Hit(n = None, *, k = None)
   :canonical: lenskit.metrics.ranking._hit.Hit

   Bases: :py:obj:`lenskit.metrics.ranking._base.ListMetric`, :py:obj:`lenskit.metrics.ranking._base.RankingMetricBase`


   Compute whether or not a list is a hit; any list with at least one
   relevant item in the first :math:`k` positions (:math:`L_{\le k} \cap
   I_u^{\mathrm{test}} \ne \emptyset`) is scored as 1, and lists with no
   relevant items as 0.  When averaged over the recommendation lists, this
   computes the *hit rate* :cite:p:`deshpande:iknn`.

   :Stability: Caller


   .. py:property:: label

      The metric's default label in output.
      The base implementation returns the class name by default.


   .. py:method:: measure_list(recs, test)

      Compute measurements for a single list.

      :returns:

                - A float for simple metrics
                - Intermediate data for decomposed metrics
                - A dict mapping metric names to values for multi-metric classes