PartialKeyResult
================

.. cpp:class:: pandas::PartialKeyResult

   pandas C++ class.

Example
-------

.. code-block:: cpp

   #include <pandas/pandas.h>
   using namespace pandas;

   // Use PartialKeyResult
   PartialKeyResult obj;
   // ... operations ...

Type Checking
-------------

.. list-table::
   :widths: 40 20 15 25
   :header-rows: 1

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``bool is_single_level() const { return single_index.has_value()``
     - bool
     - pd_multiindex.h:3273
     - :ref:`View <example-partialkeyresult-is_single_level-0>`


Code Examples
-------------

The following examples are extracted from the test suite.

.. _example-partialkeyresult-is_single_level-0:

.. dropdown:: is_single_level (pd_test_3_all.cpp:26357)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 26347
      :emphasize-lines: 11

          std::vector<std::vector<std::string>> arrays = {
              {"foo", "foo", "bar", "bar"},
              {"one", "two", "one", "two"}
          };
          std::vector<std::optional<std::string>> names = {"first", "second"};
          auto mi = ::pandas::MultiIndex::from_arrays<std::string>(arrays, names);
      
          auto pk = ::pandas::select_by_first_level(mi,"foo");
          if (pk.matched_indices.size() != 2) throw std::runtime_error("Expected 2 matches for 'foo'");
          if (pk.matched_indices[0] != 0 || pk.matched_indices[1] != 1) throw std::runtime_error("Wrong indices for 'foo'");
          if (!pk.is_single_level()) throw std::runtime_error("Expected single level for 2-level MI");
          auto idx = *pk.single_index;
          if (idx.size() != 2) throw std::runtime_error("Expected index size 2");
          if (idx[0] != "one" || idx[1] != "two") throw std::runtime_error("Wrong index values");
          if (!idx.name().has_value() || *idx.name() != "second") throw std::runtime_error("Wrong index name");
          std::cout << "    PASSED" << std::endl;
      }
      
      void pd_test_multiindex_partial_key_bar() {
          std::cout << "  Testing select_by_first_level 2-level 'bar'..." << std::endl;
          std::vector<std::vector<std::string>> arrays = {