Dataset
=======

.. cpp:class:: pandas::Dataset

   Utility class for pandas operations.

Example
-------

.. code-block:: cpp

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

   // Use Dataset
   Dataset obj;
   // ... operations ...

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

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

   * - Signature
     - Location
     - Example
   * - ``Dataset(const std::map<std::string, DataVarVariant>& data_vars, const std::map<std::string, Coordinate>& coords = {}, const std::map<std::string, std::string>& attrs = {})``
     - pd_xarray.h:467
     - 

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

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``const std::map<std::string, std::string>& attrs() const``
     - const std::map<std::string, std::string>&
     - pd_xarray.h:503
     - :ref:`View <example-dataset-attrs-0>`
   * - ``std::map<std::string, std::string>& attrs()``
     - std::map<std::string, std::string>&
     - pd_xarray.h:504
     - :ref:`View <example-dataset-attrs-1>`

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

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``void drop_var(const std::string& name)``
     - void
     - pd_xarray.h:574
     - 

Statistics
----------

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``std::vector<std::string> var_names() const``
     - std::vector<std::string>
     - pd_xarray.h:514
     - :ref:`View <example-dataset-var_names-2>`

I/O
---

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``std::string to_string() const``
     - std::string
     - pd_xarray.h:625
     - :ref:`View <example-dataset-to_string-3>`

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

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``void compute_dims()``
     - void
     - pd_xarray.h:718
     - 
   * - ``const Coordinate& coord(const std::string& name) const``
     - const Coordinate&
     - pd_xarray.h:593
     - :ref:`View <example-dataset-coord-4>`
   * - ``const std::map<std::string, Coordinate>& coords() const``
     - const std::map<std::string, Coordinate>&
     - pd_xarray.h:492
     - :ref:`View <example-dataset-coords-5>`
   * - ``std::map<std::string, Coordinate>& coords()``
     - std::map<std::string, Coordinate>&
     - pd_xarray.h:493
     - :ref:`View <example-dataset-coords-6>`
   * - ``const std::map<std::string, DataVarVariant>& data_vars() const``
     - const std::map<std::string, DataVarVariant>&
     - pd_xarray.h:486
     - 
   * - ``std::map<std::string, DataVarVariant>& data_vars()``
     - std::map<std::string, DataVarVariant>&
     - pd_xarray.h:487
     - 
   * - ``std::vector<std::string> dim_names() const``
     - std::vector<std::string>
     - pd_xarray.h:526
     - 
   * - ``const std::map<std::string, size_t>& dims() const``
     - const std::map<std::string, size_t>&
     - pd_xarray.h:498
     - :ref:`View <example-dataset-dims-7>`
   * - ``bool empty() const { return data_vars_.empty()``
     - bool
     - pd_xarray.h:538
     - :ref:`View <example-dataset-empty-8>`
   * - ``bool has_coord(const std::string& name) const``
     - bool
     - pd_xarray.h:586
     - :ref:`View <example-dataset-has_coord-9>`
   * - ``bool has_var(const std::string& name) const``
     - bool
     - pd_xarray.h:547
     - :ref:`View <example-dataset-has_var-10>`
   * - ``size_t nvars() const { return data_vars_.size()``
     - size_t
     - pd_xarray.h:509
     - :ref:`View <example-dataset-nvars-11>`
   * - ``void recompute_dims()``
     - void
     - pd_xarray.h:614
     - 
   * - ``void set_coord(const std::string& name, const Coordinate& coord)``
     - void
     - pd_xarray.h:604
     - 
   * - ``void set_var(const std::string& name, const DataArray<T>& var)``
     - void
     - pd_xarray.h:566
     - 


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

The following examples are extracted from the test suite.

.. _example-dataset-attrs-0:

.. dropdown:: attrs (pd_test_1_all.cpp:16361)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 16351
      :emphasize-lines: 11

              // =====================================================================
              // Series Attrs Integration Tests
              // =====================================================================
      
              void pd_test_ndframe_series_attrs() {
                  std::cout << "========= series attrs integration =============================" << std::endl;
      
                  pandas::Series<double> s({1.0, 2.0, 3.0});
      
                  // Test setting attrs on Series
                  s.attrs().set("source", std::string("test_data"));
                  s.attrs().set("timestamp", 1234567890);
      
                  bool passed = s.attrs().get<std::string>("source") == "test_data";
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_ndframe_series_attrs() : set/get source" << std::endl;
                      throw std::runtime_error("pd_test_ndframe_series_attrs failed: set/get source");
                  }
      
                  passed = s.attrs().get<int>("timestamp") == 1234567890;
                  if (!passed) {

.. _example-dataset-attrs-1:

.. dropdown:: attrs (pd_test_1_all.cpp:16361)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 16351
      :emphasize-lines: 11

              // =====================================================================
              // Series Attrs Integration Tests
              // =====================================================================
      
              void pd_test_ndframe_series_attrs() {
                  std::cout << "========= series attrs integration =============================" << std::endl;
      
                  pandas::Series<double> s({1.0, 2.0, 3.0});
      
                  // Test setting attrs on Series
                  s.attrs().set("source", std::string("test_data"));
                  s.attrs().set("timestamp", 1234567890);
      
                  bool passed = s.attrs().get<std::string>("source") == "test_data";
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_ndframe_series_attrs() : set/get source" << std::endl;
                      throw std::runtime_error("pd_test_ndframe_series_attrs failed: set/get source");
                  }
      
                  passed = s.attrs().get<int>("timestamp") == 1234567890;
                  if (!passed) {

.. _example-dataset-var_names-2:

.. dropdown:: var_names (pd_test_2_all.cpp:17312)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 17302
      :emphasize-lines: 11

                  pandas::DataFrame df(data);
                  pandas::Dataset ds = df.to_xarray();
      
                  // Verify single variable
                  bool passed = (ds.nvars() == 1 && ds.has_var("value"));
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_to_xarray_single_column() : expected single 'value' variable" << std::endl;
                      throw std::runtime_error("pd_test_to_xarray_single_column failed");
                  }
      
                  // Verify var_names()
                  auto names = ds.var_names();
                  passed = (names.size() == 1 && names[0] == "value");
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_to_xarray_single_column() : wrong var_names" << std::endl;
                      throw std::runtime_error("pd_test_to_xarray_single_column failed: wrong var_names");
                  }
      
                  std::cout << " -> tests passed" << std::endl;
              }
      

.. _example-dataset-to_string-3:

.. 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-dataset-coord-4:

.. dropdown:: coord (pd_test_2_all.cpp:17025)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 17015
      :emphasize-lines: 11

      
                  // Create DataFrame with RangeIndex (default)
                  std::map<std::string, std::vector<numpy::float64>> data = {
                      {"val", {1.0, 2.0, 3.0}}
                  };
      
                  pandas::DataFrame df(data);
                  pandas::Dataset ds = df.to_xarray();
      
                  // Get index coordinate
                  const pandas::Coordinate& idx_coord = ds.coord("index");
      
                  // Verify coordinate size
                  bool passed = (idx_coord.size() == 3);
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_to_xarray_coordinate_values() : wrong coordinate size" << std::endl;
                      throw std::runtime_error("pd_test_to_xarray_coordinate_values failed: wrong size");
                  }
      
                  // Verify coordinate values (0, 1, 2 for RangeIndex)
                  passed = (idx_coord.get_value_str(0) == "0" &&

.. _example-dataset-coords-5:

.. dropdown:: coords (pd_test_3_all.cpp:14912)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 14902
      :emphasize-lines: 11

      /**
       * Test Series.to_xarray() coordinates
       */
      void pd_test_series_to_xarray_coordinates() {
          std::cout << "========= Series.to_xarray() coordinates ===============";
      
          pandas::Series<double> s({100.0, 200.0, 300.0}, "prices");
          pandas::DataArray<double> da = s.to_xarray();
      
          // Verify coordinate exists
          auto& coords = da.coords();
          if (coords.find("index") == coords.end()) {
              std::cout << "  [FAIL] : should have 'index' coordinate" << std::endl;
              throw std::runtime_error("pd_test_series_to_xarray_coordinates failed: missing coord");
          }
      
          // Verify coordinate size matches Series
          const pandas::Coordinate& coord = coords.at("index");
          if (coord.size() != 3) {
              std::cout << "  [FAIL] : coordinate size should be 3, got " << coord.size() << std::endl;
              throw std::runtime_error("pd_test_series_to_xarray_coordinates failed: coord size");

.. _example-dataset-coords-6:

.. dropdown:: coords (pd_test_3_all.cpp:14912)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 14902
      :emphasize-lines: 11

      /**
       * Test Series.to_xarray() coordinates
       */
      void pd_test_series_to_xarray_coordinates() {
          std::cout << "========= Series.to_xarray() coordinates ===============";
      
          pandas::Series<double> s({100.0, 200.0, 300.0}, "prices");
          pandas::DataArray<double> da = s.to_xarray();
      
          // Verify coordinate exists
          auto& coords = da.coords();
          if (coords.find("index") == coords.end()) {
              std::cout << "  [FAIL] : should have 'index' coordinate" << std::endl;
              throw std::runtime_error("pd_test_series_to_xarray_coordinates failed: missing coord");
          }
      
          // Verify coordinate size matches Series
          const pandas::Coordinate& coord = coords.at("index");
          if (coord.size() != 3) {
              std::cout << "  [FAIL] : coordinate size should be 3, got " << coord.size() << std::endl;
              throw std::runtime_error("pd_test_series_to_xarray_coordinates failed: coord size");

.. _example-dataset-dims-7:

.. dropdown:: dims (pd_test_2_all.cpp:16997)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 16987
      :emphasize-lines: 11

                  // Create DataFrame with 4 rows
                  std::map<std::string, std::vector<numpy::int64>> data = {
                      {"x", {10, 20, 30, 40}},
                      {"y", {100, 200, 300, 400}}
                  };
      
                  pandas::DataFrame df(data);
                  pandas::Dataset ds = df.to_xarray();
      
                  // Verify dimensions
                  auto dims = ds.dims();
                  bool passed = (dims.size() == 1 && dims.count("index") == 1 && dims.at("index") == 4);
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_to_xarray_dimensions() : wrong dimensions" << std::endl;
                      std::cout << "    Expected: index: 4" << std::endl;
                      std::cout << "    Got: ";
                      for (const auto& [name, size] : dims) {
                          std::cout << name << ": " << size << " ";
                      }
                      std::cout << std::endl;
                      throw std::runtime_error("pd_test_to_xarray_dimensions failed");

.. _example-dataset-empty-8:

.. dropdown:: empty (pd_test_1_all.cpp:941)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 931
      :emphasize-lines: 11

      
      #include "../pandas/pd_config.h"
      
      namespace dataframe_tests {
      
      namespace dataframe_tests_config {
      
          void pd_test_config_version() {
              std::cout << "========= df_config: version info ======================= ";
              const char* version = pandas::DataFrameInfo::version();
              if (version == nullptr || std::string(version).empty()) {
                  std::cout << "[FAIL] : in pd_test_config_version() : version is null or empty" << std::endl;
                  throw std::runtime_error("pd_test_config_version failed: version is null or empty");
              }
              std::cout << "-> tests passed" << std::endl;
          }
      
          void pd_test_config_na_repr() {
              std::cout << "========= df_config: NA representation ======================= ";
              const char* na_repr = pandas::DataFrameConfig::get_na_repr();
              if (na_repr == nullptr) {

.. _example-dataset-has_coord-9:

.. dropdown:: has_coord (pd_test_2_all.cpp:16975)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 16965
      :emphasize-lines: 11

                  }
      
                  // Verify variable names
                  passed = ds.has_var("A") && ds.has_var("B");
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_to_xarray_basic() : missing variable A or B" << std::endl;
                      throw std::runtime_error("pd_test_to_xarray_basic failed: missing variables");
                  }
      
                  // Verify coordinate exists
                  passed = ds.has_coord("index");
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_to_xarray_basic() : missing index coordinate" << std::endl;
                      throw std::runtime_error("pd_test_to_xarray_basic failed: missing index coordinate");
                  }
      
                  std::cout << " -> tests passed" << std::endl;
              }
      
              void pd_test_to_xarray_dimensions() {
                  std::cout << "========= to_xarray dimensions =========================";

.. _example-dataset-has_var-10:

.. dropdown:: has_var (pd_test_2_all.cpp:16968)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 16958
      :emphasize-lines: 11

      
                  // Verify Dataset has correct structure
                  bool passed = (ds.nvars() == 2);
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_to_xarray_basic() : expected 2 variables, got "
                                << ds.nvars() << std::endl;
                      throw std::runtime_error("pd_test_to_xarray_basic failed: wrong number of variables");
                  }
      
                  // Verify variable names
                  passed = ds.has_var("A") && ds.has_var("B");
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_to_xarray_basic() : missing variable A or B" << std::endl;
                      throw std::runtime_error("pd_test_to_xarray_basic failed: missing variables");
                  }
      
                  // Verify coordinate exists
                  passed = ds.has_coord("index");
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_to_xarray_basic() : missing index coordinate" << std::endl;
                      throw std::runtime_error("pd_test_to_xarray_basic failed: missing index coordinate");

.. _example-dataset-nvars-11:

.. dropdown:: nvars (pd_test_2_all.cpp:16960)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 16950
      :emphasize-lines: 11

                      {"A", {1.0, 2.0, 3.0}},
                      {"B", {4.0, 5.0, 6.0}}
                  };
      
                  pandas::DataFrame df(data);
      
                  // Convert to xarray Dataset
                  pandas::Dataset ds = df.to_xarray();
      
                  // Verify Dataset has correct structure
                  bool passed = (ds.nvars() == 2);
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_to_xarray_basic() : expected 2 variables, got "
                                << ds.nvars() << std::endl;
                      throw std::runtime_error("pd_test_to_xarray_basic failed: wrong number of variables");
                  }
      
                  // Verify variable names
                  passed = ds.has_var("A") && ds.has_var("B");
                  if (!passed) {
                      std::cout << "  [FAIL] : in pd_test_to_xarray_basic() : missing variable A or B" << std::endl;