DataFrameRolling
================

.. cpp:class:: pandas::DataFrameRolling

   Window operation class for rolling/expanding calculations.

Example
-------

.. code-block:: cpp

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

   // Use DataFrameRolling
   DataFrameRolling obj;
   // ... operations ...

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

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

   * - Signature
     - Location
     - Example
   * - ``DataFrameRolling(const DataFrame& df, size_t window, size_t min_periods = 1, bool center = false)``
     - pd_dataframe.h:12632
     - 

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

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``const DataFrame& get_df() const``
     - const DataFrame&
     - pd_dataframe.h:12654
     - 

Statistics
----------

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``size_t min_periods() const``
     - size_t
     - pd_dataframe.h:12652
     - 

Aggregation
-----------

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``DataFrame apply_to_columns(Func&& func) const``
     - DataFrame
     - pd_dataframe.h:12690
     - 

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

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

   * - Signature
     - Return Type
     - Location
     - Example
   * - ``bool center() const``
     - bool
     - pd_dataframe.h:12653
     - :ref:`View <example-dataframerolling-center-0>`
   * - ``Rolling<double> select_column(const std::string& col) const``
     - Rolling<double>
     - pd_dataframe.h:12656
     - 
   * - ``void set_custom_bounds(std::vector<int64_t> start, std::vector<int64_t> end)``
     - void
     - pd_dataframe.h:12645
     - 
   * - ``void set_on_column(const std::string& col)``
     - void
     - pd_dataframe.h:12643
     - 
   * - ``void set_time_window(std::vector<int64_t> timestamps, int64_t window_seconds, int closed = 0)``
     - void
     - pd_dataframe.h:12635
     - 
   * - ``size_t window() const``
     - size_t
     - pd_dataframe.h:12651
     - :ref:`View <example-dataframerolling-window-1>`


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

The following examples are extracted from the test suite.

.. _example-dataframerolling-center-0:

.. dropdown:: center (pd_test_3_all.cpp:21005)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 20995
      :emphasize-lines: 11

          auto alnum_result = s.str().isalnum();
          if (alnum_result[0] != true || alnum_result[1] != true || alnum_result[2] != true || alnum_result[3] != false) {
              std::cout << "  [FAIL] : isalnum() failed" << std::endl;
              throw std::runtime_error("pd_test_str_is_methods: isalnum() failed");
          }
      
          std::cout << " -> tests passed" << std::endl;
      }
      
      // ============================================================================
      // Test str().zfill(), str().center(), str().ljust(), str().rjust()
      // ============================================================================
      
      void pd_test_str_padding() {
          std::cout << "========= Series.str().zfill/center/ljust/rjust() =======";
      
          pandas::Series<std::string> s({"1", "22", "333"});
      
          auto zfill_result = s.str().zfill(5);
          if (zfill_result[0] != "00001" || zfill_result[1] != "00022" || zfill_result[2] != "00333") {
              std::cout << "  [FAIL] : zfill() failed" << std::endl;

.. _example-dataframerolling-window-1:

.. dropdown:: window (pd_test_1_all.cpp:20977)
   :class-title: example-dropdown

   .. code-block:: cpp
      :linenos:
      :lineno-start: 20967
      :emphasize-lines: 11

                      }
                      throw std::runtime_error("pd_test_expanding_corr failed: expanding corr values incorrect");
                  }
      
                  std::cout << " -> tests passed" << std::endl;
              }
      
              void pd_test_expanding_skew() {
                  std::cout << "========= Expanding skew ========================";
      
                  // Symmetric data: skew should be 0 at each expanding window (starting from 3)
                  pandas::Series<double> s({1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0});
                  auto result = s.expanding().skew();
      
                  // First 2 should be NaN (need >= 3 values)
                  // Symmetric expanding windows [1,2,3], [1,2,3,4], ... all have skew = 0
                  bool passed = std::isnan(result[0]) &&
                                std::isnan(result[1]) &&
                                std::abs(result[2] - 0.0) < 0.001 &&
                                std::abs(result[3] - 0.0) < 0.001 &&
                                std::abs(result[4] - 0.0) < 0.001;