DataFrameSparseAccessor
=======================

.. cpp:class:: pandas::DataFrameSparseAccessor

   pandas C++ class.

Example
-------

.. code-block:: cpp

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

   // Use DataFrameSparseAccessor
   DataFrameSparseAccessor obj;
   // ... operations ...

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

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

   * - Signature
     - Location
     - Example
   * - ``explicit DataFrameSparseAccessor(const DataFrame& parent)``
     - pd_sparse_accessor.h:181
     - 

Construction
------------

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``static DataFrame from_spmatrix( const std::vector<double>& data, const std::vector<size_t>& row_idx, const std::vector<size_t>& col_idx, size_t nrows, size_t ncols, const std::vector<std::string>& index = {}, const std::vector<std::string>& columns = {})``
     - static DataFrame
     - pd_sparse_accessor.h:208
     - 

I/O
---

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``to_coo() const``
     - 
     - pd_sparse_accessor.h:202
     - :ref:`View <example-dataframesparseaccessor-to_coo-0>`
   * - ``DataFrame to_dense() const``
     - DataFrame
     - pd_sparse_accessor.h:194
     - :ref:`View <example-dataframesparseaccessor-to_dense-1>`

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

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``double density() const``
     - double
     - pd_sparse_accessor.h:188
     - :ref:`View <example-dataframesparseaccessor-density-2>`


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

The following examples are extracted from the test suite.

.. _example-dataframesparseaccessor-to_coo-0:

.. dropdown:: to_coo (pd_test_3_all.cpp:21918)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 21908
      :emphasize-lines: 11

              throw std::runtime_error("SparseAccessor.to_dense(): wrong size");
          }
          if (dense[0] != 0.0 || dense[1] != 1.0 || dense[2] != 0.0 || dense[3] != 2.0) {
              throw std::runtime_error("SparseAccessor.to_dense(): wrong values");
          }
      
          std::cout << " -> tests passed" << std::endl;
      }
      
      void test_sparse_to_coo() {
          std::cout << "========= SparseAccessor.to_coo() ==================";
      
          pandas::Series<numpy::float64> s({0.0, 1.0, 0.0, 2.0, 0.0});
          auto sparse = s.sparse();
      
          auto [data, rows, cols, shape] = sparse.to_coo();
          if (data.size() != 2) {
              throw std::runtime_error("SparseAccessor.to_coo(): expected 2 data points");
          }
          if (data[0] != 1.0 || data[1] != 2.0) {
              throw std::runtime_error("SparseAccessor.to_coo(): wrong data values");

.. _example-dataframesparseaccessor-to_dense-1:

.. dropdown:: to_dense (pd_test_1_all.cpp:3272)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 3262
      :emphasize-lines: 11

      
              std::cout << " -> tests passed" << std::endl;
          }
      
          void pd_test_sparse_array_to_dense() {
              std::cout << "========= SparseArray: to_dense ======================= ";
      
              std::vector<numpy::float64> data = {0.0, 1.0, 0.0, 2.0, 0.0};
              pandas::SparseArray<numpy::float64> arr(data, 0.0);
      
              auto dense = arr.to_dense();
              if (dense.getSize() != 5) {
                  std::cout << "  [FAIL] : in pd_test_sparse_array_to_dense() : dense size != 5" << std::endl;
                  throw std::runtime_error("pd_test_sparse_array_to_dense failed: dense size != 5");
              }
      
              if (dense.getElementAt({0}) != 0.0 ||
                  dense.getElementAt({1}) != 1.0 ||
                  dense.getElementAt({2}) != 0.0 ||
                  dense.getElementAt({3}) != 2.0 ||
                  dense.getElementAt({4}) != 0.0) {

.. _example-dataframesparseaccessor-density-2:

.. dropdown:: density (pd_test_1_all.cpp:3247)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 3237
      :emphasize-lines: 11

                  std::cout << "  [FAIL] : in pd_test_sparse_array_fill_value_property() : default float fill_value should be NaN" << std::endl;
                  throw std::runtime_error("pd_test_sparse_array_fill_value_property failed: default float fill_value should be NaN");
              }
      
              std::cout << " -> tests passed" << std::endl;
          }
      
          void pd_test_sparse_array_density() {
              std::cout << "========= SparseArray: density ======================= ";
      
              // 20% density (2 non-fill out of 10)
              std::vector<numpy::float64> data = {0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 2.0, 0.0};
              pandas::SparseArray<numpy::float64> arr(data, 0.0);
      
              double density = arr.density();
              if (std::abs(density - 0.2) > 0.001) {
                  std::cout << "  [FAIL] : in pd_test_sparse_array_density() : density != 0.2, got " << density << std::endl;
                  throw std::runtime_error("pd_test_sparse_array_density failed: density != 0.2");
              }
      
              double sparsity = arr.sparsity();