minerva.data.readers.tabular_reader
===================================

.. py:module:: minerva.data.readers.tabular_reader


Classes
-------

.. autoapisummary::

   minerva.data.readers.tabular_reader.TabularReader


Module Contents
---------------

.. py:class:: TabularReader(df, columns_to_select, cast_to = None, data_shape = None)

   Bases: :py:obj:`minerva.data.readers.reader._Reader`


   Base class for readers. Readers define an ordered collection of data and
   provide methods to access it. This class primarily handles:

   1. Definition of data structure and storage.
   2. Reading data from the source.

   The access is handled by the __getitem__ and __len__ methods, which should be
   implemented by a subclass. Readers usually returns a single item at a time,
   that can be a single image, a single label, etc.

   Reader to select columns from a DataFrame and return them as a NumPy
   array. The DataFrame is indexed by the row number. Each row of the
   DataFrame is considered as a sample. Thus, the __getitem__ method will
   return the columns of the DataFrame at the specified index as a NumPy
   array.

   Parameters
   ----------
   df : pd.DataFrame
       The DataFrame to select the columns from. The DataFrame should have
       the columns that are specified in the `columns_to_select` parameter.
   columns_to_select : Union[str, list[str]]
       A string or a list of strings used to select the columns from the
       DataFrame. The string can be a regular expression pattern or a
       column name. The columns that match the pattern will be selected.
       Note that if columns_to_select is a list, the result is always a
       numpy array with the columns in the same order as the list.
       If the columns_to_select is a string, the result is a numpy array
       if the selected columns are more than one, otherwise it is a single
       value (which is not a numpy array).
   cast_to : str, optional
       Cast the selected columns to the specified data type. If None, the
       data type of the columns will not be changed. (default is None)
   data_shape : tuple[int, ...], optional
       The shape of the data to be returned. If None, the data will be
       returned as a 1D array. If provided, the data will be reshaped to
       the specified shape. (default is None)


   .. py:method:: __getitem__(index)

      Return the columns of the DataFrame at the specified row index as a NumPy
      array. The columns are selected based on the `self.columns_to_select`.

      Parameters
      ----------
      index : int
          The row index to select the columns from the DataFrame.

      Returns
      -------
      np.ndarray
          The selected columns from the row as a NumPy array.



   .. py:method:: __len__()

      Return the number of samples in the DataFrame. The number of samples
      is equal to the number of rows in the DataFrame.

      Returns
      -------
      int
          The number of samples in the DataFrame.



   .. py:method:: __str__()

      Return a string representation of the TabularReader object.

      Returns
      -------
      str
          A string representation of the TabularReader object.



   .. py:attribute:: cast_to
      :value: None



   .. py:attribute:: columns_to_select


   .. py:attribute:: data_shape
      :value: None



   .. py:attribute:: df


   .. py:attribute:: return_single
      :value: False