NDArrayBackedExtensionIndex
===========================

.. cpp:class:: pandas::NDArrayBackedExtensionIndex

   Index class for axis labels in pandas data structures.

Example
-------

.. code-block:: cpp

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

   // Create NDArrayBackedExtensionIndex
   NDArrayBackedExtensionIndex<int64_t> idx({1, 2, 3}, "my_index");
   size_t len = idx.size();

Constructors
------------

.. list-table::
   :widths: 55 25 20
   :header-rows: 1

   * - Signature
     - Location
     - Example
   * - ``explicit NDArrayBackedExtensionIndex(const ArrayType& array, const std::optional<std::string>& name = std::nullopt, bool copy = false)``
     - pd_ndarray_backed_extension_index.h:141
     - 
   * - ``explicit NDArrayBackedExtensionIndex(ArrayType&& array, const std::optional<std::string>& name = std::nullopt)``
     - pd_ndarray_backed_extension_index.h:151
     - 
   * - ``NDArrayBackedExtensionIndex(const NDArrayBackedExtensionIndex& other)``
     - pd_ndarray_backed_extension_index.h:160
     - 
   * - ``NDArrayBackedExtensionIndex(NDArrayBackedExtensionIndex&& other) noexcept``
     - pd_ndarray_backed_extension_index.h:168
     - 

Indexing / Selection
--------------------

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``std::string get_value_str(size_t index) const override``
     - std::string
     - pd_ndarray_backed_extension_index.h:705
     - :ref:`View <example-ndarraybackedextensionindex-get_value_str-0>`

Data Manipulation
-----------------

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``NDArrayBackedExtensionIndex rename(const std::optional<std::string>& new_name) const``
     - NDArrayBackedExtensionIndex
     - pd_ndarray_backed_extension_index.h:757
     - :ref:`View <example-ndarraybackedextensionindex-rename-1>`

I/O
---

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``std::string to_string() const override``
     - std::string
     - pd_ndarray_backed_extension_index.h:618
     - :ref:`View <example-ndarraybackedextensionindex-to_string-2>`

Conversion
----------

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``NDArrayBackedExtensionIndex copy() const``
     - NDArrayBackedExtensionIndex
     - pd_ndarray_backed_extension_index.h:750
     - :ref:`View <example-ndarraybackedextensionindex-copy-3>`

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

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``bool is_all_dates() const``
     - bool
     - pd_ndarray_backed_extension_index.h:489
     - :ref:`View <example-ndarraybackedextensionindex-is_all_dates-4>`

Other Methods
-------------

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``DatetimeArray arr(data, mask)``
     - DatetimeArray
     - pd_ndarray_backed_extension_index.h:279
     - :ref:`View <example-ndarraybackedextensionindex-arr-5>`
   * - ``TimedeltaArray arr(data, mask)``
     - TimedeltaArray
     - pd_ndarray_backed_extension_index.h:296
     - :ref:`View <example-ndarraybackedextensionindex-arr-6>`
   * - ``DatetimeArray arr(data, mask)``
     - DatetimeArray
     - pd_ndarray_backed_extension_index.h:349
     - :ref:`View <example-ndarraybackedextensionindex-arr-7>`
   * - ``TimedeltaArray arr(data, mask)``
     - TimedeltaArray
     - pd_ndarray_backed_extension_index.h:365
     - :ref:`View <example-ndarraybackedextensionindex-arr-8>`
   * - ``PeriodArray arr(data, mask, "D")``
     - PeriodArray
     - pd_ndarray_backed_extension_index.h:379
     - :ref:`View <example-ndarraybackedextensionindex-arr-9>`
   * - ``PeriodArray arr(data, mask, freq)``
     - PeriodArray
     - pd_ndarray_backed_extension_index.h:405
     - :ref:`View <example-ndarraybackedextensionindex-arr-10>`
   * - ``size_t cache_memory_usage() const override``
     - size_t
     - pd_ndarray_backed_extension_index.h:957
     - 
   * - ``void clear_cache() const override``
     - void
     - pd_ndarray_backed_extension_index.h:938
     - :ref:`View <example-ndarraybackedextensionindex-clear_cache-11>`
   * - ``std::unique_ptr<IndexBase> clone() const override``
     - std::unique_ptr<IndexBase>
     - pd_ndarray_backed_extension_index.h:607
     - :ref:`View <example-ndarraybackedextensionindex-clone-12>`
   * - ``static std::string format_datetime(const numpy::datetime64& val)``
     - static std::string
     - pd_ndarray_backed_extension_index.h:771
     - 
   * - ``std::string format_period(numpy::int64 ordinal) const``
     - std::string
     - pd_ndarray_backed_extension_index.h:920
     - 
   * - ``static std::string format_timedelta(const numpy::timedelta64& val)``
     - static std::string
     - pd_ndarray_backed_extension_index.h:846
     - 
   * - ``std::string freq_string() const``
     - std::string
     - pd_ndarray_backed_extension_index.h:566
     - :ref:`View <example-ndarraybackedextensionindex-freq_string-13>`
   * - ``bool has_cached_values() const override``
     - bool
     - pd_ndarray_backed_extension_index.h:948
     - :ref:`View <example-ndarraybackedextensionindex-has_cached_values-14>`
   * - ``std::string inferred_type() const override``
     - std::string
     - pd_ndarray_backed_extension_index.h:593
     - :ref:`View <example-ndarraybackedextensionindex-inferred_type-15>`
   * - ``PeriodArray arr(data, mask, period_freq_to_string(current_arr.freq()))``
     - PeriodArray arr(data, mask,
     - pd_ndarray_backed_extension_index.h:312
     - 
   * - ``std::string repr() const override``
     - std::string
     - pd_ndarray_backed_extension_index.h:698
     - :ref:`View <example-ndarraybackedextensionindex-repr-16>`
   * - ``std::string resolution() const``
     - std::string
     - pd_ndarray_backed_extension_index.h:427
     - :ref:`View <example-ndarraybackedextensionindex-resolution-17>`
   * - ``NDArrayBackedExtensionIndex result(\*this)``
     - NDArrayBackedExtensionIndex
     - pd_ndarray_backed_extension_index.h:758
     - :ref:`View <example-ndarraybackedextensionindex-result-18>`
   * - ``IndexTypeId type_id() const override``
     - IndexTypeId
     - pd_ndarray_backed_extension_index.h:611
     - :ref:`View <example-ndarraybackedextensionindex-type_id-19>`
   * - ``std::string unit() const``
     - std::string
     - pd_ndarray_backed_extension_index.h:528
     - :ref:`View <example-ndarraybackedextensionindex-unit-20>`
   * - ``static std::string unit_to_string(numpy::DateTimeUnit unit)``
     - static std::string
     - pd_ndarray_backed_extension_index.h:543
     - 

Internal Methods
----------------

*6 internal methods (prefixed with underscore)*


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

The following examples are extracted from the test suite.

.. _example-ndarraybackedextensionindex-get_value_str-0:

.. dropdown:: get_value_str (pd_test_1_all.cpp:4665)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 4655
      :emphasize-lines: 11

                  auto corr_df = df.corr();
      
                  // Check dimensions
                  bool passed = corr_df.nrows() == 2 && corr_df.ncols() == 2;
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_aggregation_dataframe_corr() : corr should be 2x2" << std::endl;
                      throw std::runtime_error("pd_test_aggregation_dataframe_corr failed: corr should be 2x2");
                  }
      
                  // Diagonal should be 1.0
                  std::string aa = corr_df["A"].get_value_str(0);
                  passed = std::abs(std::stod(aa) - 1.0) < 0.001;
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_aggregation_dataframe_corr() : diagonal should be 1.0" << std::endl;
                      throw std::runtime_error("pd_test_aggregation_dataframe_corr failed: diagonal should be 1.0");
                  }
      
                  // A-B correlation should be 1.0 (perfect correlation)
                  std::string ab = corr_df["B"].get_value_str(0);
                  passed = std::abs(std::stod(ab) - 1.0) < 0.001;
                  if (!passed) {

.. _example-ndarraybackedextensionindex-rename-1:

.. dropdown:: rename (pd_test_1_all.cpp:5816)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 5806
      :emphasize-lines: 11

      
          std::cout << " -> tests passed" << std::endl;
      }
      
      void pd_test_categorical_index_rename() {
          std::cout << "========= rename ======================================";
      
          pandas::CategoricalArray arr({"x", "y"});
          pandas::CategoricalIndex idx(arr, "old_name");
      
          pandas::CategoricalIndex renamed = idx.rename("new_name");
      
          bool passed = (renamed.name().has_value() && *renamed.name() == "new_name" &&
                         renamed.size() == idx.size() && renamed.categories() == idx.categories());
          if (!passed) {
              std::cout << "  [FAIL] : in pd_test_categorical_index_rename()" << std::endl;
              throw std::runtime_error("pd_test_categorical_index_rename failed");
          }
      
          std::cout << " -> tests passed" << std::endl;
      }

.. _example-ndarraybackedextensionindex-to_string-2:

.. dropdown:: to_string (pd_test_1_all.cpp:2693)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 2683
      :emphasize-lines: 11

              pandas::PeriodArray arr_m(std::vector<std::string>{
                  "2020-01",
                  "NaT",
                  "2025-06"
              }, "M");
      
              // Year
              auto years = arr_m.year();
              auto y0 = years[0];
              if (!y0.has_value() || y0.value() != 2020) {
                  std::cout << "  [FAIL] : year[0] should be 2020, got " << (y0.has_value() ? std::to_string(y0.value()) : "NA") << std::endl;
                  throw std::runtime_error("pd_test_period_array_year_month_quarter failed: year[0]");
              }
      
              auto y1 = years[1];
              if (y1.has_value()) {
                  std::cout << "  [FAIL] : year[1] should be NA (NaT)" << std::endl;
                  throw std::runtime_error("pd_test_period_array_year_month_quarter failed: year[1] should be NA");
              }
      
              auto y2 = years[2];

.. _example-ndarraybackedextensionindex-copy-3:

.. dropdown:: copy (pd_test_1_all.cpp:5798)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 5788
      :emphasize-lines: 11

      // ============================================================================
      // Copy/Rename Tests
      // ============================================================================
      
      void pd_test_categorical_index_copy() {
          std::cout << "========= copy ========================================";
      
          pandas::CategoricalArray arr({"a", "b", "c"});
          pandas::CategoricalIndex idx(arr, "original");
      
          pandas::CategoricalIndex copied = idx.copy();
      
          bool passed = (copied.size() == idx.size() && copied.name() == idx.name() &&
                         copied.categories() == idx.categories() && copied.ordered() == idx.ordered());
          if (!passed) {
              std::cout << "  [FAIL] : in pd_test_categorical_index_copy()" << std::endl;
              throw std::runtime_error("pd_test_categorical_index_copy failed");
          }
      
          std::cout << " -> tests passed" << std::endl;
      }

.. _example-ndarraybackedextensionindex-is_all_dates-4:

.. dropdown:: is_all_dates (pd_test_1_all.cpp:15606)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 15596
      :emphasize-lines: 11

          bool passed = (res == "day");
          if (!passed) {
              std::cout << "  [FAIL] : in pd_test_period_index_resolution() : resolution check failed, got: " << res << std::endl;
              throw std::runtime_error("pd_test_period_index_resolution failed");
          }
      
          std::cout << " -> tests passed" << std::endl;
      }
      
      // ============================================================================
      // is_all_dates() Tests
      // ============================================================================
      
      void pd_test_is_all_dates() {
          std::cout << "========= is_all_dates() =========================";
      
          // DatetimeIndex
          numpy::NDArray<numpy::datetime64> dt_data(std::vector<size_t>{1});
          dt_data.setElementAt({0}, numpy::datetime64(1000LL, numpy::DateTimeUnit::Nanosecond));
          numpy::NDArray<numpy::bool_> dt_mask(std::vector<size_t>{1});
          dt_mask.setElementAt({0}, numpy::bool_(false));

.. _example-ndarraybackedextensionindex-arr-5:

.. dropdown:: arr (pd_test_1_all.cpp:45)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 35
      :emphasize-lines: 11

                  std::cout << "  [FAIL] : in pd_test_boolean_array_constructors() : initializer_list size != 4" << std::endl;
                  throw std::runtime_error("pd_test_boolean_array_constructors failed: initializer_list size != 4");
              }
      
              std::cout << " -> tests passed" << std::endl;
          }
      
          void pd_test_boolean_array_na_handling() {
              std::cout << "========= BooleanArray: NA handling ======================= ";
      
              pandas::BooleanArray arr({
                  std::optional<bool>(true),
                  std::nullopt,  // NA at index 1
                  std::optional<bool>(false)
              });
      
              if (!arr.is_na(1)) {
                  std::cout << "  [FAIL] : in pd_test_boolean_array_na_handling() : is_na(1) should be true" << std::endl;
                  throw std::runtime_error("pd_test_boolean_array_na_handling failed: is_na(1) should be true");
              }
      

.. _example-ndarraybackedextensionindex-arr-6:

.. dropdown:: arr (pd_test_1_all.cpp:45)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 35
      :emphasize-lines: 11

                  std::cout << "  [FAIL] : in pd_test_boolean_array_constructors() : initializer_list size != 4" << std::endl;
                  throw std::runtime_error("pd_test_boolean_array_constructors failed: initializer_list size != 4");
              }
      
              std::cout << " -> tests passed" << std::endl;
          }
      
          void pd_test_boolean_array_na_handling() {
              std::cout << "========= BooleanArray: NA handling ======================= ";
      
              pandas::BooleanArray arr({
                  std::optional<bool>(true),
                  std::nullopt,  // NA at index 1
                  std::optional<bool>(false)
              });
      
              if (!arr.is_na(1)) {
                  std::cout << "  [FAIL] : in pd_test_boolean_array_na_handling() : is_na(1) should be true" << std::endl;
                  throw std::runtime_error("pd_test_boolean_array_na_handling failed: is_na(1) should be true");
              }
      

.. _example-ndarraybackedextensionindex-arr-7:

.. dropdown:: arr (pd_test_1_all.cpp:45)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 35
      :emphasize-lines: 11

                  std::cout << "  [FAIL] : in pd_test_boolean_array_constructors() : initializer_list size != 4" << std::endl;
                  throw std::runtime_error("pd_test_boolean_array_constructors failed: initializer_list size != 4");
              }
      
              std::cout << " -> tests passed" << std::endl;
          }
      
          void pd_test_boolean_array_na_handling() {
              std::cout << "========= BooleanArray: NA handling ======================= ";
      
              pandas::BooleanArray arr({
                  std::optional<bool>(true),
                  std::nullopt,  // NA at index 1
                  std::optional<bool>(false)
              });
      
              if (!arr.is_na(1)) {
                  std::cout << "  [FAIL] : in pd_test_boolean_array_na_handling() : is_na(1) should be true" << std::endl;
                  throw std::runtime_error("pd_test_boolean_array_na_handling failed: is_na(1) should be true");
              }
      

.. _example-ndarraybackedextensionindex-arr-8:

.. dropdown:: arr (pd_test_1_all.cpp:45)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 35
      :emphasize-lines: 11

                  std::cout << "  [FAIL] : in pd_test_boolean_array_constructors() : initializer_list size != 4" << std::endl;
                  throw std::runtime_error("pd_test_boolean_array_constructors failed: initializer_list size != 4");
              }
      
              std::cout << " -> tests passed" << std::endl;
          }
      
          void pd_test_boolean_array_na_handling() {
              std::cout << "========= BooleanArray: NA handling ======================= ";
      
              pandas::BooleanArray arr({
                  std::optional<bool>(true),
                  std::nullopt,  // NA at index 1
                  std::optional<bool>(false)
              });
      
              if (!arr.is_na(1)) {
                  std::cout << "  [FAIL] : in pd_test_boolean_array_na_handling() : is_na(1) should be true" << std::endl;
                  throw std::runtime_error("pd_test_boolean_array_na_handling failed: is_na(1) should be true");
              }
      

.. _example-ndarraybackedextensionindex-arr-9:

.. dropdown:: arr (pd_test_1_all.cpp:45)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 35
      :emphasize-lines: 11

                  std::cout << "  [FAIL] : in pd_test_boolean_array_constructors() : initializer_list size != 4" << std::endl;
                  throw std::runtime_error("pd_test_boolean_array_constructors failed: initializer_list size != 4");
              }
      
              std::cout << " -> tests passed" << std::endl;
          }
      
          void pd_test_boolean_array_na_handling() {
              std::cout << "========= BooleanArray: NA handling ======================= ";
      
              pandas::BooleanArray arr({
                  std::optional<bool>(true),
                  std::nullopt,  // NA at index 1
                  std::optional<bool>(false)
              });
      
              if (!arr.is_na(1)) {
                  std::cout << "  [FAIL] : in pd_test_boolean_array_na_handling() : is_na(1) should be true" << std::endl;
                  throw std::runtime_error("pd_test_boolean_array_na_handling failed: is_na(1) should be true");
              }
      

.. _example-ndarraybackedextensionindex-arr-10:

.. dropdown:: arr (pd_test_1_all.cpp:45)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 35
      :emphasize-lines: 11

                  std::cout << "  [FAIL] : in pd_test_boolean_array_constructors() : initializer_list size != 4" << std::endl;
                  throw std::runtime_error("pd_test_boolean_array_constructors failed: initializer_list size != 4");
              }
      
              std::cout << " -> tests passed" << std::endl;
          }
      
          void pd_test_boolean_array_na_handling() {
              std::cout << "========= BooleanArray: NA handling ======================= ";
      
              pandas::BooleanArray arr({
                  std::optional<bool>(true),
                  std::nullopt,  // NA at index 1
                  std::optional<bool>(false)
              });
      
              if (!arr.is_na(1)) {
                  std::cout << "  [FAIL] : in pd_test_boolean_array_na_handling() : is_na(1) should be true" << std::endl;
                  throw std::runtime_error("pd_test_boolean_array_na_handling failed: is_na(1) should be true");
              }
      

.. _example-ndarraybackedextensionindex-clear_cache-11:

.. dropdown:: clear_cache (pd_test_1_all.cpp:19413)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 19403
      :emphasize-lines: 11

                  s.mean();
                  s.min();
                  s.max();
      
                  passed = s.has_cached_values() == true;
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_series_cache() : cache not populated" << std::endl;
                      throw std::runtime_error("pd_test_series_cache failed: cache not populated");
                  }
      
                  s.clear_cache();
                  passed = s.has_cached_values() == false;
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_series_cache() : cache not cleared" << std::endl;
                      throw std::runtime_error("pd_test_series_cache failed: cache not cleared");
                  }
      
                  std::cout << " -> tests passed" << std::endl;
              }
      
              void pd_test_series_string_repr() {

.. _example-ndarraybackedextensionindex-clone-12:

.. dropdown:: clone (pd_test_1_all.cpp:5776)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 5766
      :emphasize-lines: 11

      
          std::cout << " -> tests passed" << std::endl;
      }
      
      void pd_test_categorical_index_clone() {
          std::cout << "========= clone =======================================";
      
          pandas::CategoricalArray arr({"p", "q", "r"});
          pandas::CategoricalIndex idx(arr, "original");
      
          std::unique_ptr<pandas::IndexBase> cloned = idx.clone();
      
          bool passed = (cloned != nullptr && cloned->size() == idx.size() &&
                         cloned->name() == idx.name());
          if (!passed) {
              std::cout << "  [FAIL] : in pd_test_categorical_index_clone()" << std::endl;
              throw std::runtime_error("pd_test_categorical_index_clone failed");
          }
      
          std::cout << " -> tests passed" << std::endl;
      }

.. _example-ndarraybackedextensionindex-freq_string-13:

.. dropdown:: freq_string (pd_test_1_all.cpp:15733)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 15723
      :emphasize-lines: 11

          bool passed = (isnan_mask.size() == 2);
          if (!passed) {
              std::cout << "  [FAIL] : in pd_test_period_index_isnan() : _isnan check failed" << std::endl;
              throw std::runtime_error("pd_test_period_index_isnan failed");
          }
      
          std::cout << " -> tests passed" << std::endl;
      }
      
      // ============================================================================
      // unit() and freq_string() Tests
      // ============================================================================
      
      void pd_test_unit_freq_string() {
          std::cout << "========= unit() / freq_string() =========================";
      
          // PeriodIndex with monthly frequency
          numpy::NDArray<numpy::int64> data(std::vector<size_t>{1});
          data.setElementAt({0}, numpy::int64(0));
      
          numpy::NDArray<numpy::bool_> mask(std::vector<size_t>{1});

.. _example-ndarraybackedextensionindex-has_cached_values-14:

.. dropdown:: has_cached_values (pd_test_1_all.cpp:19395)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 19385
      :emphasize-lines: 11

                  }
      
                  std::cout << " -> tests passed" << std::endl;
              }
      
              void pd_test_series_cache() {
                  std::cout << "========= cache management =========================================";
      
                  pandas::Series<double> s({1.0, 2.0, 3.0, 4.0, 5.0});
      
                  bool passed = s.has_cached_values() == false;
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_series_cache() : initial cache not empty" << std::endl;
                      throw std::runtime_error("pd_test_series_cache failed: initial cache not empty");
                  }
      
                  // Trigger cache
                  s.sum();
                  s.mean();
                  s.min();
                  s.max();

.. _example-ndarraybackedextensionindex-inferred_type-15:

.. dropdown:: inferred_type (pd_test_1_all.cpp:5270)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 5260
      :emphasize-lines: 11

      }
      
      void pd_test_categorical_index_array_constructor() {
          std::cout << "========= array constructor ===========================";
      
          pandas::CategoricalArray arr({"apple", "banana", "apple", "cherry"});
          pandas::CategoricalIndex idx(arr, "fruits");
      
          bool passed = (idx.size() == 4 && !idx.empty() &&
                         idx.name().has_value() && *idx.name() == "fruits" &&
                         idx.inferred_type() == "categorical");
          if (!passed) {
              std::cout << "  [FAIL] : in pd_test_categorical_index_array_constructor()" << std::endl;
              throw std::runtime_error("pd_test_categorical_index_array_constructor failed");
          }
      
          std::cout << " -> tests passed" << std::endl;
      }
      
      void pd_test_categorical_index_values_constructor() {
          std::cout << "========= values constructor ==========================";

.. _example-ndarraybackedextensionindex-repr-16:

.. dropdown:: repr (pd_test_1_all.cpp:10906)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 10896
      :emphasize-lines: 11

          std::cout << " -> tests passed" << std::endl;
      }
      
      void pd_test_extension_index_repr() {
          std::cout << "========= repr =========================";
      
          pandas::CategoricalArray arr({"a", "b", "c"});
          // Use ExtensionIndex<CategoricalArray> directly to test base class repr
          pandas::ExtensionIndex<pandas::CategoricalArray> idx(arr, "test");
      
          std::string repr_str = idx.repr();
      
          bool passed = (!repr_str.empty() && repr_str.find("ExtensionIndex") != std::string::npos);
          if (!passed) {
              std::cout << "  [FAIL] : in pd_test_extension_index_repr() : repr check failed" << std::endl;
              throw std::runtime_error("pd_test_extension_index_repr failed");
          }
      
          std::cout << " -> tests passed" << std::endl;
      }
      

.. _example-ndarraybackedextensionindex-resolution-17:

.. dropdown:: resolution (pd_test_1_all.cpp:15536)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 15526
      :emphasize-lines: 11

          }
      
          std::cout << " -> tests passed" << std::endl;
      }
      
      // ============================================================================
      // Resolution Tests
      // ============================================================================
      
      void pd_test_datetime_index_resolution() {
          std::cout << "========= DatetimeIndex resolution() =========================";
      
          numpy::NDArray<numpy::datetime64> data(std::vector<size_t>{1});
          data.setElementAt({0}, numpy::datetime64(1000LL, numpy::DateTimeUnit::Nanosecond));
      
          numpy::NDArray<numpy::bool_> mask(std::vector<size_t>{1});
          mask.setElementAt({0}, numpy::bool_(false));
      
          pandas::DatetimeArray arr(data, mask);
          pandas::DatetimeIndexBase idx(arr);
      

.. _example-ndarraybackedextensionindex-result-18:

.. dropdown:: result (pd_test_1_all.cpp:15406)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 15396
      :emphasize-lines: 11

          data.setElementAt({0}, numpy::datetime64(100LL, numpy::DateTimeUnit::Nanosecond));
          data.setElementAt({1}, numpy::datetime64(200LL, numpy::DateTimeUnit::Nanosecond));
      
          numpy::NDArray<numpy::bool_> mask(std::vector<size_t>{2});
          mask.setElementAt({0}, numpy::bool_(false));
          mask.setElementAt({1}, numpy::bool_(false));
      
          pandas::DatetimeArray arr(data, mask);
          pandas::DatetimeIndexBase idx(arr, "original");
      
          // Create join result (int64 values)
          numpy::NDArray<numpy::int64> join_result(std::vector<size_t>{3});
          join_result.setElementAt({0}, numpy::int64(500LL));
          join_result.setElementAt({1}, numpy::int64(600LL));
          join_result.setElementAt({2}, numpy::int64(700LL));
      
          auto new_idx = idx._from_join_target(join_result);
      
          bool passed = (new_idx.size() == 3 &&
                         new_idx.name().has_value() && *new_idx.name() == "original");
          if (!passed) {

.. _example-ndarraybackedextensionindex-type_id-19:

.. dropdown:: type_id (pd_test_3_all.cpp:25592)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 25582
      :emphasize-lines: 11

      // ------------------- pd_test_value_classify (end) ------------------
      
      // ------------------- pd_test_index_type_id (start) ------------------
      namespace dataframe_tests_index_type_id {
      
      void pd_test_index_type_id_dispatch() {
          std::cout << "========= IndexTypeId dispatch =======================";
      
          // RangeIndex
          ::pandas::RangeIndex ri(0, 5);
          if (ri.type_id() != ::pandas::IndexTypeId::RangeIndex)
              throw std::runtime_error("RangeIndex type_id failed");
      
          // Index<string>
          ::pandas::Index<std::string> si(std::vector<std::string>{"a", "b", "c"});
          if (si.type_id() != ::pandas::IndexTypeId::IndexString)
              throw std::runtime_error("Index<string> type_id failed");
      
          // Index<int64>
          ::pandas::Index<numpy::int64> ii(std::vector<numpy::int64>{1, 2, 3});
          if (ii.type_id() != ::pandas::IndexTypeId::IndexInt64)

.. _example-ndarraybackedextensionindex-unit-20:

.. dropdown:: unit (pd_test_1_all.cpp:9284)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 9274
      :emphasize-lines: 11

          data.setElementAt({0}, numpy::datetime64(1000LL, numpy::DateTimeUnit::Nanosecond));
          data.setElementAt({1}, numpy::datetime64(2000LL, numpy::DateTimeUnit::Nanosecond));
      
          numpy::NDArray<numpy::bool_> mask(std::vector<size_t>{2});
          mask.setElementAt({0}, numpy::bool_(false));
          mask.setElementAt({1}, numpy::bool_(false));
      
          pandas::DatetimeArray arr(data, mask);
          pandas::DatetimeTDMixin idx(arr);
      
          std::string unit = idx.unit();
      
          bool passed = (unit == "ns");  // nanosecond
          if (!passed) {
              std::cout << "  [FAIL] : in pd_test_datetime_unit_property() : unit property check failed, got '" << unit << "'" << std::endl;
              throw std::runtime_error("pd_test_datetime_unit_property failed");
          }
      
          std::cout << " -> tests passed" << std::endl;
      }