docs/changes/latest.inc

@@ -50,3 +50,7 @@ API changes
 
 - Add ``confounds_format`` parameter to :class:`junifer.datagrabber.PatternDataGrabber` constructor for
   improved handling of confounds specified via ``BOLD_confounds`` data type (:gh:`158` by `Synchon Mandal`_).
+
+- Rename ``store_table()`` to ``store_vector()`` for storage-like objects and adapt marker-like objects to
+  use ``"vector"`` in place of ``"table"`` for storage. Also, improve the logic of storing vectors
+  (:gh:`181` by `Synchon Mandal`_).

docs/understanding/storage.rst

@@ -15,10 +15,10 @@ that object else they are kept in memory.
 Storage is meant to be used inside the datagrabber context but you can operate on them outside the context as long
 as the processed data is in the memory and the Python runtime has not garbage-collected it.
 
-The :ref:`Markers <marker>` are responsible for defining what *storage kind* (``matrix``, ``table``, ``timeseries``)
+The :ref:`Markers <marker>` are responsible for defining what *storage kind* (``matrix``, ``vector``, ``timeseries``)
 they support for which :ref:`data type <data_types>` by overriding its ``store`` method. The storage object in turn
 declares and provides implementation for specific *storage kind*. For example, :class:`junifer.storage.SQLiteFeatureStorage`
-supports saving ``matrix``, ``table`` and ``timeseries`` via ``store_matrix``, ``store_table`` and ``store_timeseries``
+supports saving ``matrix``, ``vector`` and ``timeseries`` via ``store_matrix``, ``store_vector`` and ``store_timeseries``
 methods respectively.
 
 For storage interfaces not supported by junifer yet, you can either make your own ``Storage`` by providing a concrete
@@ -42,10 +42,10 @@ Currently supported storage types
      - A 2D matrix with row and column names
      -  ``col_names``, ``row_names``, ``matrix_kind``, ``diagonal``
      -  :meth:`junifer.storage.BaseFeatureStorage.store_matrix`
-   * - ``table``
+   * - ``vector``
      - A vector of values with column names
      - ``columns``, ``row_names``
-     -  :meth:`junifer.storage.BaseFeatureStorage.store_table`
+     -  :meth:`junifer.storage.BaseFeatureStorage.store_vector`
    * - ``timeseries``
      - A 2D matrix of values with column names
      - ``columns``, ``row_names``

junifer/data/masks.py

@@ -7,24 +7,23 @@ from pathlib import Path
 from typing import (
     TYPE_CHECKING,
     Any,
+    Callable,
     Dict,
     List,
     Optional,
     Tuple,
     Union,
-    Callable,
 )
 
-import numpy as np
-
 import nibabel as nib
-from nilearn.masking import (
+import numpy as np
-    compute_brain_mask,
-    compute_background_mask,
-    compute_epi_mask,
-)
 from nilearn.datasets import fetch_icbm152_brain_gm_mask
 from nilearn.image import resample_to_img
+from nilearn.masking import (
+    compute_background_mask,
+    compute_brain_mask,
+    compute_epi_mask,
+)
 
 from ..utils.logging import logger, raise_error
 from .utils import closest_resolution

junifer/data/tests/test_masks.py

@@ -5,33 +5,27 @@
 #          Synchon Mandal <s.mandal@fz-juelich.de>
 # License: AGPL
 
+from pathlib import Path
 from typing import Callable, Dict, Union
 
-from pathlib import Path
-
 import pytest
-from numpy.testing import (
+from nilearn.datasets import fetch_icbm152_brain_gm_mask
-    assert_array_almost_equal,
-    assert_array_equal,
-)
-
 from nilearn.image import resample_to_img
 from nilearn.masking import (
-    compute_brain_mask,
     compute_background_mask,
+    compute_brain_mask,
     compute_epi_mask,
 )
-from nilearn.datasets import fetch_icbm152_brain_gm_mask
+from numpy.testing import assert_array_almost_equal, assert_array_equal
 
 from junifer.data.masks import (
+    _available_masks,
     _load_vickery_patil_mask,
+    get_mask,
     list_masks,
     load_mask,
     register_mask,
-    get_mask,
-    _available_masks,
 )
-
 from junifer.datareader import DefaultDataReader
 from junifer.testing.datagrabbers import (
     OasisVBMTestingDatagrabber,

junifer/datagrabber/tests/test_hcp.py

@@ -3,11 +3,11 @@
 # Authors: Synchon Mandal <s.mandal@fz-juelich.de>
 # License: AGPL
 
-from typing import Optional, Iterable
+from typing import Iterable, Optional
 
 import pytest
 
-from junifer.datagrabber.hcp import DataladHCP1200, HCP1200
+from junifer.datagrabber.hcp import HCP1200, DataladHCP1200
 from junifer.utils import configure_logging
 
 
@@ -332,9 +332,7 @@ def test_hcp1200_datagrabber_elements(
     )
     with dg:
         # Get all elements
-        expected_subjects = [
+        expected_subjects = [f"sub-{x:02d}" for x in range(1, 10)]
-            f"sub-{x:02d}" for x in range(1, 10)
-        ]
         found_subjects = []
         all_elements = dg.get_elements()
         # Check only specified task and phase encoding are found

junifer/markers/ets_rss.py

@@ -110,8 +110,7 @@ class RSSETSMarker(BaseMarker):
             keys:
 
             * ``data`` : the actual computed values as a numpy.ndarray
-            * ``columns`` : the column labels for the computed values as a list
+            * ``col_names`` : the column labels for the computed values as list
-            * ``row_names`` (if more than one row is present in data): "scan"
 
         References
         ----------
@@ -135,5 +134,5 @@ class RSSETSMarker(BaseMarker):
         # Compute the RSS
         out["data"] = np.sum(edge_ts**2, 1) ** 0.5
         # Set correct column label
-        out["columns"] = ["root_sum_of_squares_ets"]
+        out["col_names"] = ["root_sum_of_squares_ets"]
         return out

junifer/markers/falff/falff_base.py

@@ -104,7 +104,7 @@ class AmplitudeLowFrequencyFluctuationBase(BaseMarker):
             The storage type output by the marker.
 
         """
-        return "table"
+        return "vector"
 
     def compute(
         self,
@@ -132,8 +132,7 @@ class AmplitudeLowFrequencyFluctuationBase(BaseMarker):
             with this as a parameter. The dictionary has the following keys:
 
             * ``data`` : the actual computed values as a numpy.ndarray
-            * ``columns`` : the column labels for the computed values as a list
+            * ``col_names`` : the column labels for the computed values as list
-            * ``row_names`` (if more than one row is present in data): "scan"
 
         """
         if self.use_afni is None:

junifer/markers/falff/falff_parcels.py

@@ -109,7 +109,7 @@ class AmplitudeLowFrequencyFluctuationParcels(
             keys:
 
             * ``data`` : the actual computed values as a numpy.ndarray
-            * ``columns`` : the column labels for the computed values as a list
+            * ``col_names`` : the column labels for the computed values as list
 
         """
         pa = ParcelAggregation(

junifer/markers/falff/falff_spheres.py

@@ -115,7 +115,7 @@ class AmplitudeLowFrequencyFluctuationSpheres(
             keys:
 
             * ``data`` : the actual computed values as a numpy.ndarray
-            * ``columns`` : the column labels for the computed values as a list
+            * ``col_names`` : the column labels for the computed values as list
 
         """
         pa = SphereAggregation(

junifer/markers/functional_connectivity/crossparcellation_functional_connectivity.py

@@ -150,6 +150,6 @@ class CrossParcellationFC(BaseMarker):
 
         return {
             "data": result,
-            "col_names": parcellation_one_dict["columns"],
+            "col_names": parcellation_one_dict["col_names"],
-            "row_names": parcellation_two_dict["columns"],
+            "row_names": parcellation_two_dict["col_names"],
         }

junifer/markers/functional_connectivity/edge_functional_connectivity_parcels.py

@@ -84,7 +84,7 @@ class EdgeCentricFCParcels(FunctionalConnectivityBase):
 
         bold_aggregated = parcel_aggregation.compute(input)
         ets, edge_names = _ets(
-            bold_aggregated["data"], bold_aggregated["columns"]
+            bold_aggregated["data"], bold_aggregated["col_names"]
         )
 
-        return dict(data=ets, columns=edge_names)
+        return {"data": ets, "col_names": edge_names}

junifer/markers/functional_connectivity/edge_functional_connectivity_spheres.py

@@ -91,7 +91,7 @@ class EdgeCentricFCSpheres(FunctionalConnectivityBase):
         )
         bold_aggregated = sphere_aggregation.compute(input)
         ets, edge_names = _ets(
-            bold_aggregated["data"], bold_aggregated["columns"]
+            bold_aggregated["data"], bold_aggregated["col_names"]
         )
 
-        return dict(data=ets, columns=edge_names)
+        return {"data": ets, "col_names": edge_names}

junifer/markers/functional_connectivity/functional_connectivity_base.py

@@ -143,7 +143,7 @@ class FunctionalConnectivityBase(BaseMarker):
         out = {}
         out["data"] = connectivity.fit_transform([aggregation["data"]])[0]
         # Create column names
-        out["row_names"] = aggregation["columns"]
+        out["row_names"] = aggregation["col_names"]
-        out["col_names"] = aggregation["columns"]
+        out["col_names"] = aggregation["col_names"]
         out["matrix_kind"] = "tril"
         return out

junifer/markers/parcel_aggregation.py

@@ -91,7 +91,7 @@ class ParcelAggregation(BaseMarker):
         """
 
         if input_type in ["VBM_GM", "VBM_WM", "fALFF", "GCOR", "LCOR"]:
-            return "table"
+            return "vector"
         elif input_type == "BOLD":
             return "timeseries"
         else:
@@ -123,7 +123,7 @@ class ParcelAggregation(BaseMarker):
             with this as a parameter. The dictionary has the following keys:
 
             * ``data`` : the actual computed values as a numpy.ndarray
-            * ``columns`` : the column labels for the computed values as a list
+            * ``col_names`` : the column labels for the computed values as list
 
         """
         t_input_img = input["data"]
@@ -218,5 +218,5 @@ class ParcelAggregation(BaseMarker):
             out_labels.append(labels[t_v - 1])
 
         out_values = np.array(out_values).T
-        out = {"data": out_values, "columns": out_labels}
+        out = {"data": out_values, "col_names": out_labels}
         return out

junifer/markers/reho/reho_base.py

@@ -70,7 +70,7 @@ class ReHoBase(BaseMarker):
             The storage type output by the marker.
 
         """
-        return "table"
+        return "vector"
 
     def compute_reho_map(
         self,

junifer/markers/reho/reho_parcels.py

@@ -122,8 +122,7 @@ class ReHoParcels(ReHoBase):
             keys:
 
             * ``data`` : the actual computed values as a 1D numpy.ndarray
-            * ``columns`` : the column labels for the parcels as a list
+            * ``col_names`` : the column labels for the parcels as a list
-            * ``row_names`` : ``None``
 
         """
         logger.info("Calculating ReHo for parcels.")

junifer/markers/reho/reho_spheres.py

@@ -129,8 +129,7 @@ class ReHoSpheres(ReHoBase):
             keys:
 
             * ``data`` : the actual computed values as a 1D numpy.ndarray
-            * ``columns`` : the column labels for the spheres as a list
+            * ``col_names`` : the column labels for the spheres as a list
-            * ``rows_col_name`` : ``None``
 
         """
         logger.info("Calculating ReHo for spheres.")

junifer/markers/reho/tests/test_reho_parcels.py

@@ -35,7 +35,7 @@ def test_reho_parcels_computation() -> None:
         reho_parcels_output_bold = reho_parcels_output["BOLD"]
         # Assert BOLD output keys
         assert "data" in reho_parcels_output_bold
-        assert "columns" in reho_parcels_output_bold
+        assert "col_names" in reho_parcels_output_bold
 
         reho_parcels_output_bold_data = reho_parcels_output_bold["data"]
         # Assert BOLD output data dimension

junifer/markers/reho/tests/test_reho_spheres.py

@@ -35,7 +35,7 @@ def test_reho_spheres_computation() -> None:
         reho_spheres_output_bold = reho_spheres_output["BOLD"]
         # Assert BOLD output keys
         assert "data" in reho_spheres_output_bold
-        assert "columns" in reho_spheres_output_bold
+        assert "col_names" in reho_spheres_output_bold
 
         reho_spheres_output_bold_data = reho_spheres_output_bold["data"]
         # Assert BOLD output data dimension

junifer/markers/sphere_aggregation.py

@@ -7,7 +7,7 @@
 from typing import Any, Dict, List, Optional, Union
 
 from ..api.decorators import register_marker
-from ..data import load_coordinates, get_mask
+from ..data import get_mask, load_coordinates
 from ..external.nilearn import JuniferNiftiSpheresMasker
 from ..stats import get_aggfunc_by_name
 from ..utils import logger
@@ -94,7 +94,7 @@ class SphereAggregation(BaseMarker):
         """
 
         if input_type in ["VBM_GM", "VBM_WM", "fALFF", "GCOR", "LCOR"]:
-            return "table"
+            return "vector"
         elif input_type == "BOLD":
             return "timeseries"
         else:
@@ -126,7 +126,7 @@ class SphereAggregation(BaseMarker):
             with this as a parameter. The dictionary has the following keys:
 
             * ``data`` : the actual computed values as a numpy.ndarray
-            * ``columns`` : the column labels for the computed values as a list
+            * ``col_names`` : the column labels for the computed values as list
 
         """
         t_input_img = input["data"]
@@ -151,5 +151,5 @@ class SphereAggregation(BaseMarker):
         # Fit and transform the marker on the data
         out_values = masker.fit_transform(t_input_img)
         # Format the output
-        out = {"data": out_values, "columns": out_labels}
+        out = {"data": out_values, "col_names": out_labels}
         return out

junifer/markers/tests/test_collection.py

@@ -87,7 +87,7 @@ def test_marker_collection() -> None:
             assert "VBM_GM" in out[t_name]
             t_vbm = out[t_name]["VBM_GM"]
             assert "data" in t_vbm
-            assert "columns" in t_vbm
+            assert "col_names" in t_vbm
             assert "meta" in t_vbm
 
     # Test preprocessing
@@ -199,19 +199,19 @@ def test_marker_collection_storage(tmp_path: Path) -> None:
     t_feature = storage.read_df(feature_md5=feature_md5)
     fname = "gmd_schaefer100x7_mean"
     t_data = out[fname]["VBM_GM"]["data"]  # type: ignore
-    cols = out[fname]["VBM_GM"]["columns"]  # type: ignore
+    cols = out[fname]["VBM_GM"]["col_names"]  # type: ignore
     assert_array_equal(t_feature[cols].values, t_data)  # type: ignore
 
     feature_md5 = list(features.keys())[1]
     t_feature = storage.read_df(feature_md5=feature_md5)
     fname = "gmd_schaefer100x7_std"
     t_data = out[fname]["VBM_GM"]["data"]  # type: ignore
-    cols = out[fname]["VBM_GM"]["columns"]  # type: ignore
+    cols = out[fname]["VBM_GM"]["col_names"]  # type: ignore
     assert_array_equal(t_feature[cols].values, t_data)  # type: ignore
 
     feature_md5 = list(features.keys())[2]
     t_feature = storage.read_df(feature_md5=feature_md5)
     fname = "gmd_schaefer100x7_trim_mean90"
     t_data = out[fname]["VBM_GM"]["data"]  # type: ignore
-    cols = out[fname]["VBM_GM"]["columns"]  # type: ignore
+    cols = out[fname]["VBM_GM"]["col_names"]  # type: ignore
     assert_array_equal(t_feature[cols].values, t_data)  # type: ignore

junifer/markers/tests/test_parcel_aggregation.py

@@ -26,7 +26,7 @@ def test_ParcelAggregation_input_output() -> None:
     marker = ParcelAggregation(
         parcellation="Schaefer100x7", method="mean", on="VBM_GM"
     )
-    for in_, out_ in [("VBM_GM", "table"), ("BOLD", "timeseries")]:
+    for in_, out_ in [("VBM_GM", "vector"), ("BOLD", "timeseries")]:
         assert marker.get_output_type(in_) == out_
 
     with pytest.raises(ValueError, match="Unknown input"):
@@ -364,7 +364,7 @@ def test_ParcelAggregation_3D_multiple_non_overlapping(tmp_path: Path) -> None:
 
     # Data and labels should be the same
     assert_array_equal(orig_mean_data, split_mean_data)
-    assert orig_mean["columns"] == split_mean["columns"]
+    assert orig_mean["col_names"] == split_mean["col_names"]
 
 
 def test_ParcelAggregation_3D_multiple_overlapping(tmp_path: Path) -> None:
@@ -446,5 +446,5 @@ def test_ParcelAggregation_3D_multiple_overlapping(tmp_path: Path) -> None:
     assert_array_equal(orig_mean_data, split_mean_data)
 
     # Labels should be "low" for the first 50 and "high" for the second 50
-    assert all(x.startswith("low") for x in split_mean["columns"][:50])
+    assert all(x.startswith("low") for x in split_mean["col_names"][:50])
-    assert all(x.startswith("high") for x in split_mean["columns"][50:])
+    assert all(x.startswith("high") for x in split_mean["col_names"][50:])

junifer/markers/tests/test_sphere_aggregation.py

@@ -27,7 +27,7 @@ RADIUS = 8
 def test_SphereAggregation_input_output() -> None:
     """Test SphereAggregation input and output types."""
     marker = SphereAggregation(coords="DMNBuckner", method="mean", on="VBM_GM")
-    for in_, out_ in [("VBM_GM", "table"), ("BOLD", "timeseries")]:
+    for in_, out_ in [("VBM_GM", "vector"), ("BOLD", "timeseries")]:
         assert marker.get_output_type(in_) == out_
 
     with pytest.raises(ValueError, match="Unknown input"):

junifer/storage/base.py

@@ -6,7 +6,7 @@
 
 from abc import ABC, abstractmethod
 from pathlib import Path
-from typing import Dict, Iterable, List, Optional, Union
+from typing import Any, Dict, Iterable, List, Optional, Union
 
 import numpy as np
 import pandas as pd
@@ -57,8 +57,9 @@ class BaseFeatureStorage(ABC):
         Returns
         -------
         list of str
-            The list of storage types that can be used as input for this "
+            The list of storage types that can be used as input for this
-            "storage.
+            storage interface.
+
         """
         raise_error(
             msg="Concrete classes need to implement get_valid_inputs().",
@@ -87,15 +88,15 @@ class BaseFeatureStorage(ABC):
             )
 
     @abstractmethod
-    def list_features(self) -> Dict:
+    def list_features(self) -> Dict[str, Dict[str, Any]]:
         """List the features in the storage.
 
         Returns
         -------
         dict
-            List of features in the storage. The keys are the feature names to
+            List of features in the storage. The keys are the feature MD5 to
-            be used in read_features() and the values are the metadata of each
+            be used in :meth:`junifer.storage.BaseFeatureStorage.read_df`
-            feature.
+            and the values are the metadata of each feature.
 
         """
         raise_error(
@@ -107,7 +108,7 @@ class BaseFeatureStorage(ABC):
     def read_df(
         self,
         feature_name: Optional[str] = None,
-        feature_md5: Optional[bool] = None,
+        feature_md5: Optional[str] = None,
     ) -> pd.DataFrame:
         """Read feature into a pandas DataFrame.
 
@@ -152,7 +153,7 @@ class BaseFeatureStorage(ABC):
 
         Parameters
         ----------
-        kind : {"matrix", "timeseries", "table"}
+        kind : {"matrix", "timeseries", "vector"}
             The storage kind.
         **kwargs
             The keyword arguments.
@@ -179,8 +180,8 @@ class BaseFeatureStorage(ABC):
             self.store_timeseries(
                 meta_md5=meta_md5, element=t_element, **kwargs
             )
-        elif kind == "table":
+        elif kind == "vector":
-            self.store_table(meta_md5=meta_md5, element=t_element, **kwargs)
+            self.store_vector(meta_md5=meta_md5, element=t_element, **kwargs)
 
     def store_matrix(
         self,
@@ -203,11 +204,9 @@ class BaseFeatureStorage(ABC):
         data : numpy.ndarray
             The matrix data to store.
         col_names : list or tuple of str, optional
-            The column names (default None).
+            The column labels (default None).
         row_names : str, optional
-            The column name to use in case number of rows greater than 1.
+            The row labels (default None).
-            If None and number of rows greater than 1, then the name will be
-            "index" (default None).
         matrix_kind : str, optional
             The kind of matrix:
 
@@ -217,23 +216,23 @@ class BaseFeatureStorage(ABC):
 
             (default "full").
         diagonal : bool, optional
-            Whether to store the diagonal. If `matrix_kind` is "full", setting
+            Whether to store the diagonal. If ``matrix_kind = full``, setting
             this to False will raise an error (default True).
+
         """
         raise_error(
-            msg="Concrete classes need to implement store_matrix2d().",
+            msg="Concrete classes need to implement store_matrix().",
             klass=NotImplementedError,
         )
 
-    def store_table(
+    def store_vector(
         self,
         meta_md5: str,
         element: Dict,
         data: Union[np.ndarray, List],
-        columns: Optional[Iterable[str]] = None,
+        col_names: Optional[Iterable[str]] = None,
-        rows_col_name: Optional[str] = None,
     ) -> None:
-        """Store table.
+        """Store vector.
 
         Parameters
         ----------
@@ -242,16 +241,13 @@ class BaseFeatureStorage(ABC):
         element : dict
             The element as a dictionary.
         data : numpy.ndarray or list
-            The table data to store.
+            The vector data to store.
-        columns : list or tuple of str, optional
+        col_names : list or tuple of str, optional
-            The columns (default None).
+            The column labels (default None).
-        rows_col_name : str, optional
+
-            The column name to use in case number of rows greater than 1.
-            If None and number of rows greater than 1, then the name will be
-            "index" (default None).
         """
         raise_error(
-            msg="Concrete classes need to implement store_table().",
+            msg="Concrete classes need to implement store_vector().",
             klass=NotImplementedError,
         )
 
@@ -260,9 +256,9 @@ class BaseFeatureStorage(ABC):
         meta_md5: str,
         element: Dict,
         data: np.ndarray,
-        columns: Optional[Iterable[str]] = None,
+        col_names: Optional[Iterable[str]] = None,
     ) -> None:
-        """Implement timeseries storing.
+        """Store timeseries.
 
         Parameters
         ----------
@@ -272,8 +268,9 @@ class BaseFeatureStorage(ABC):
             The element as a dictionary.
         data : numpy.ndarray
             The timeseries data to store.
-        columns : list or tuple of str, optional
+        col_names : list or tuple of str, optional
             The column labels (default None).
+
         """
         raise_error(
             msg="Concrete classes need to implement store_timeseries().",

junifer/storage/pandas_base.py

@@ -6,11 +6,12 @@
 
 import json
 from pathlib import Path
-from typing import Any, Dict, Iterable, List, Optional, Union
+from typing import Dict, Iterable, List, Optional, Union
 
 import numpy as np
 import pandas as pd
 
+from ..utils import raise_error
 from .base import BaseFeatureStorage
 
 
@@ -46,10 +47,11 @@ class PandasBaseFeatureStorage(BaseFeatureStorage):
         Returns
         -------
         list of str
-            The list of storage types that can be used as input for this "
+            The list of storage types that can be used as input for this
-            "storage.
+            storage interface.
+
         """
-        return ["matrix", "table", "timeseries"]
+        return ["matrix", "vector", "timeseries"]
 
     def _meta_row(self, meta: Dict, meta_md5: str) -> pd.DataFrame:
         """Convert the metadata to a pandas DataFrame.
@@ -76,7 +78,7 @@ class PandasBaseFeatureStorage(BaseFeatureStorage):
     @staticmethod
     def element_to_index(
         element: Dict, n_rows: int = 1, rows_col_name: Optional[str] = None
-    ) -> pd.MultiIndex:
+    ) -> Union[pd.Index, pd.MultiIndex]:
         """Convert the element metadata to index.
 
         Parameters
@@ -86,31 +88,40 @@ class PandasBaseFeatureStorage(BaseFeatureStorage):
         n_rows : int, optional
             Number of rows to create (default 1).
         rows_col_name: str, optional
-            The column name to use in case `n_rows` > 1. If None and
+            The column name to use in case ``n_rows`` > 1. If None and
-            n_rows > 1, the name will be "idx" (default None).
+            ``n_rows`` > 1, the name will be "idx" (default None).
 
         Returns
         -------
-        pandas.MultiIndex
+        pandas.Index or pandas.MultiIndex
             The index of the dataframe to store.
 
-        Raises
-        ------
-        ValueError
-            If `meta` does not contain the key "element".
-
         """
-        # Check rows_col_name
+        # Make mapping between element access keys and values
-        if rows_col_name is None:
+        elem_idx: Dict[str, Iterable[str]] = {
-            rows_col_name = "idx"
-        elem_idx: Dict[Any, Any] = {
             k: [v] * n_rows for k, v in element.items()
         }
+
+        # Set rows_col_name if n_rows > 1 (timeseries)
+        if n_rows > 1:
+            # Set rows_col_name if None
+            if rows_col_name is None:
+                rows_col_name = "idx"
+            # Set extra column for variable number of rows per element
             elem_idx[rows_col_name] = np.arange(n_rows)
-        # Create index
+
+        # Create correct index for elements with single access variable
+        if len(elem_idx) == 1:
+            # Create normal index for vector
+            index = pd.Index(
+                data=list(elem_idx.values())[0], name=list(elem_idx.keys())[0]
+            )
+        else:
+            # Create multiindex for timeseries
             index = pd.MultiIndex.from_frame(
                 pd.DataFrame(elem_idx, index=range(n_rows))
             )
+
         return index
 
     def store_df(
@@ -132,17 +143,20 @@ class PandasBaseFeatureStorage(BaseFeatureStorage):
             generated from the metadata.
 
         """
-        raise NotImplementedError("Implement in subclass.")
+        raise_error(
+            msg="Concrete classes need to implement store_df().",
+            klass=NotImplementedError,
+        )
 
     def _store_2d(
         self,
         meta_md5: str,
         element: Dict,
         data: Union[np.ndarray, List],
-        columns: Optional[Iterable[str]] = None,
+        col_names: Optional[Iterable[str]] = None,
         rows_col_name: Optional[str] = None,
     ) -> None:
-        """Store 2D dataframe.
+        """Store 2D data.
 
         Parameters
         ----------
@@ -150,37 +164,35 @@ class PandasBaseFeatureStorage(BaseFeatureStorage):
             The metadata MD5 hash.
         element : dict
             The element as a dictionary.
-        data : numpy.ndarray or List
+        data : numpy.ndarray or list
             The data to store.
-        columns : list or tuple of str, optional
+        col_names : list or tuple of str, optional
-            The columns (default None).
+            The column labels (default None).
         rows_col_name : str, optional
             The column name to use in case number of rows greater than 1.
             If None and number of rows greater than 1, then the name will be
-            "index" (default None).
+            "idx" (default None).
 
         """
-        n_rows = len(data)
         # Convert element metadata to index
         idx = self.element_to_index(
-            element=element, n_rows=n_rows, rows_col_name=rows_col_name
+            element=element, n_rows=len(data), rows_col_name=rows_col_name
         )
         # Prepare new dataframe
-        data_df = pd.DataFrame(  # type: ignore
+        df = pd.DataFrame(
-            data, columns=columns, index=idx  # type: ignore
+            data=data, columns=col_names, index=idx  # type: ignore
         )
         # Store dataframe
-        self.store_df(meta_md5=meta_md5, element=element, df=data_df)
+        self.store_df(meta_md5=meta_md5, element=element, df=df)
 
-    def store_table(
+    def store_vector(
         self,
         meta_md5: str,
         element: Dict,
         data: Union[np.ndarray, List],
-        columns: Optional[Iterable[str]] = None,
+        col_names: Optional[Iterable[str]] = None,
-        rows_col_name: Optional[str] = None,
     ) -> None:
-        """Implement table storing.
+        """Store vector.
 
         Parameters
         ----------
@@ -188,21 +200,27 @@ class PandasBaseFeatureStorage(BaseFeatureStorage):
             The metadata MD5 hash.
         element : dict
             The element as a dictionary.
-        data : numpy.ndarray or List
+        data : numpy.ndarray or list
-            The table data to store.
+            The vector data to store.
-        columns : list or tuple of str, optional
+        col_names : list or tuple of str, optional
-            The columns (default None).
+            The column labels (default None).
-        rows_col_name : str, optional
+
-            The column name to use in case number of rows greater than 1.
-            If None and number of rows greater than 1, then the name will be
-            "index" (default None).
         """
+        if isinstance(data, list):
+            # Flatten out list and convert to np.ndarray
+            processed_data = np.array(np.ravel(data))
+        elif isinstance(data, np.ndarray):
+            # Flatten out array
+            processed_data = data.ravel()
+
+        # Make it 2D
+        processed_data = processed_data[np.newaxis, :]
+
         self._store_2d(
             meta_md5=meta_md5,
             element=element,
             data=data,
-            columns=columns,
+            col_names=col_names,
-            rows_col_name=rows_col_name,
         )
 
     def store_timeseries(
@@ -210,9 +228,9 @@ class PandasBaseFeatureStorage(BaseFeatureStorage):
         meta_md5: str,
         element: Dict,
         data: np.ndarray,
-        columns: Optional[Iterable[str]] = None,
+        col_names: Optional[Iterable[str]] = None,
     ) -> None:
-        """Implement timeseries storing.
+        """Store timeseries.
 
         Parameters
         ----------
@@ -222,13 +240,14 @@ class PandasBaseFeatureStorage(BaseFeatureStorage):
             The element as a dictionary.
         data : numpy.ndarray
             The timeseries data to store.
-        columns : list or tuple of str, optional
+        col_names : list or tuple of str, optional
             The column labels (default None).
+
         """
         self._store_2d(
             meta_md5=meta_md5,
             element=element,
             data=data,
-            columns=columns,
+            col_names=col_names,
             rows_col_name="timepoint",
         )

junifer/storage/sqlite.py

@@ -6,7 +6,7 @@
 
 import json
 from pathlib import Path
-from typing import TYPE_CHECKING, Dict, List, Optional, Union
+from typing import TYPE_CHECKING, Any, Dict, List, Optional, Union
 
 import numpy as np
 import pandas as pd
@@ -34,12 +34,12 @@ class SQLiteFeatureStorage(PandasBaseFeatureStorage):
     uri : str or pathlib.Path
         The path to the file to be used.
     single_output : bool, optional
-        If False, will create one file per element. The name
+        If False, will create one SQLite file per element. The name
         of the file will be prefixed with the respective element.
-        If True, will create only one file as specified in the `uri` and
+        If True, will create only one SQLite file as specified in the
-        store all the elements in the same file. This behaviour is only
+        ``uri`` and store all the elements in the same file. This behaviour
-        suitable for non-parallel executions. SQLite does not support
+        is only suitable for non-parallel executions. SQLite does not
-        concurrency (default True).
+        support concurrency (default True).
     upsert : {"ignore", "update"}, optional
         Upsert mode. If "ignore" is used, the existing elements are ignored.
         If "update", the existing elements are updated (default "update").
@@ -78,7 +78,7 @@ class SQLiteFeatureStorage(PandasBaseFeatureStorage):
             )
             uri.parent.mkdir(parents=True, exist_ok=True)
         # Available storage kinds
-        storage_types = ["table", "timeseries", "matrix"]
+        storage_types = ["vector", "timeseries", "matrix"]
         super().__init__(
             uri=uri,
             storage_types=storage_types,
@@ -93,8 +93,8 @@ class SQLiteFeatureStorage(PandasBaseFeatureStorage):
 
         Parameters
         ----------
-        meta : dict, optional
+        element : dict, optional
-            The metadata as dictionary (default None).
+            The element as dictionary (default None).
 
         Returns
         -------
@@ -205,24 +205,30 @@ class SQLiteFeatureStorage(PandasBaseFeatureStorage):
                         msg=f"Invalid option {if_exists} for if_exists."
                     )
 
-    def list_features(self) -> Dict:
+    def list_features(self) -> Dict[str, Dict[str, Any]]:
         """List the features in the storage.
 
         Returns
         -------
         dict
-            List of features in the storage. The keys are the feature names to
+            List of features in the storage. The keys are the feature MD5 to
-            be used in read_features() and the values are the metadata of each
+            be used in :meth:`junifer.storage.SQLiteFeatureStorage.read_df`
-            feature.
+            and the values are the metadata of each feature.
 
         """
+        # Retrieve meta table from storage
         meta_df = pd.read_sql(
             sql="meta",
             con=self.get_engine(),
             index_col="meta_md5",
         )
+        # Format index names for retrieved data
         meta_df.index = meta_df.index.str.replace(r"meta_", "")
-        out = meta_df.to_dict(orient="index")  # type: ignore
+        # Convert dataframe to dictionary
+        out: Dict[str, Dict[str, str]] = meta_df.to_dict(
+            orient="index"
+        )  # type: ignore
+        # Format output
         for md5, t_meta in out.items():
             for k, v in t_meta.items():
                 out[md5][k] = json.loads(v)
@@ -396,7 +402,7 @@ class SQLiteFeatureStorage(PandasBaseFeatureStorage):
         matrix_kind: Optional[str] = "full",
         diagonal: bool = True,
     ) -> None:
-        """Implement matrix storing.
+        """Store matrix.
 
         Parameters
         ----------
@@ -409,11 +415,9 @@ class SQLiteFeatureStorage(PandasBaseFeatureStorage):
         meta : dict
             The metadata as a dictionary.
         col_names : list or tuple of str, optional
-            The column names (default None).
+            The column labels (default None).
         row_names : str, optional
-            The column name to use in case number of rows greater than 1.
+            The row labels (optional None).
-            If None and number of rows greater than 1, then the name will be
-            "index" (default None).
         matrix_kind : str, optional
             The kind of matrix:
 
@@ -423,7 +427,7 @@ class SQLiteFeatureStorage(PandasBaseFeatureStorage):
 
             (default "full").
         diagonal : bool, optional
-            Whether to store the diagonal. If `matrix_kind` is "full", setting
+            Whether to store the diagonal. If ``matrix_kind = full``, setting
             this to False will raise an error (default True).
 
         """
@@ -470,7 +474,9 @@ class SQLiteFeatureStorage(PandasBaseFeatureStorage):
                 klass=ValueError,
             )
 
+        # Subset data
         flat_data = data[data_idx]
+        # Generate flat 1D row X column names
         columns = [
             f"{row_names[i]}~{col_names[j]}"
             for i, j in zip(data_idx[0], data_idx[1])
@@ -484,6 +490,8 @@ class SQLiteFeatureStorage(PandasBaseFeatureStorage):
         # Prepare new dataframe
         data_df = pd.DataFrame(flat_data[None, :], columns=columns, index=idx)
 
+        # SQLite's SQLITE_MAX_COLUMN is 2000, so if more than that,
+        # convert it to long format
         if len(columns) > 2000:
             warn_with_log(
                 msg="The number of columns is greater than 2000. "
@@ -510,7 +518,10 @@ class SQLiteFeatureStorage(PandasBaseFeatureStorage):
 
         """
         if self.single_output is True:
-            raise_error(msg="collect() is not implemented for single output.")
+            raise_error(
+                msg="collect() is not implemented for single output.",
+                klass=IOError,
+            )
         logger.info(
             "Collecting data from "
             f"{self.uri.parent}/*{self.uri.name}"  # type: ignore

junifer/storage/tests/test_pandas_base.py

@@ -9,62 +9,95 @@ from junifer.storage.pandas_base import PandasBaseFeatureStorage
 
 def test_element_to_index() -> None:
     """Test element to index."""
+    # First element
     element = {"foo": "bar"}
-    index = PandasBaseFeatureStorage.element_to_index(element)
-    assert index.names == ["foo", "idx"]
-    assert index.levels[0].name == "foo"
-    assert index.levels[0].values[0] == "bar"
-    assert all(x == "bar" for x in index.levels[0].values)
-    assert index.levels[0].values.shape == (1,)
-    assert index.levels[1].name == "idx"
-    assert all(x == i for i, x in enumerate(index.levels[1].values))
-    assert index.levels[1].values.shape == (1,)
 
-    index = PandasBaseFeatureStorage.element_to_index(element, n_rows=10)
+    # First test; no extra column
-    assert index.names == ["foo", "idx"]
+    index = PandasBaseFeatureStorage.element_to_index(element=element)
-    assert index.levels[0].name == "foo"
+    # Check index name
-    assert all(x == "bar" for x in index.levels[0].values)
+    assert index.name == "foo"
-    assert index.levels[0].values.shape == (1,)
+    # # Check index values
-
+    assert all(x == "bar" for x in index.values)  # type: ignore
-    assert index.levels[1].name == "idx"
+    # Check index values shape
-    assert all(x == i for i, x in enumerate(index.levels[1].values))
+    assert index.shape == (1,)  # type: ignore
-    assert index.levels[1].values.shape == (10,)
 
+    # Second test; add extra column
     index = PandasBaseFeatureStorage.element_to_index(
-        element, n_rows=1, rows_col_name="scan"
+        element=element, n_rows=10
     )
-    assert index.names == ["foo", "scan"]
+    # Check index names
-    assert index.levels[0].name == "foo"
+    assert index.names == ["foo", "idx"]
-    assert index.levels[0].values[0] == "bar"
+    # Check first index level name
-    assert all(x == "bar" for x in index.levels[0].values)
+    assert index.levels[0].name == "foo"  # type: ignore
-    assert index.levels[0].values.shape == (1,)
+    # Check first index level values
-    assert index.levels[1].name == "scan"
+    assert all(x == "bar" for x in index.levels[0].values)  # type: ignore
-    assert all(x == i for i, x in enumerate(index.levels[1].values))
+    # Check first index level values shape
-    assert index.levels[1].values.shape == (1,)
+    assert index.levels[0].values.shape == (1,)  # type: ignore
+    # Check second index level name
+    assert index.levels[1].name == "idx"  # type: ignore
+    # Check second index level values
+    assert all(
+        x == i for i, x in enumerate(index.levels[1].values)  # type: ignore
+    )
+    # Check second index level values shape
+    assert index.levels[1].values.shape == (10,)  # type: ignore
 
+    # Third test; custom extra column name has no effect
     index = PandasBaseFeatureStorage.element_to_index(
-        element, n_rows=7, rows_col_name="scan"
+        element=element, n_rows=1, rows_col_name="scan"
     )
+    # Check index name
+    assert index.name == "foo"
+    # Check index values
+    assert all(x == "bar" for x in index.values)  # type: ignore
+    # Check index values shape
+    assert index.shape == (1,)  # type: ignore
+
+    # Fourth test; custom extra column name has effect
+    index = PandasBaseFeatureStorage.element_to_index(
+        element=element, n_rows=7, rows_col_name="scan"
+    )
+    # Check index names
     assert index.names == ["foo", "scan"]
-    assert index.levels[0].name == "foo"
+    # Check first index level name
-    assert all(x == "bar" for x in index.levels[0].values)
+    assert index.levels[0].name == "foo"  # type: ignore
-    assert index.levels[0].values.shape == (1,)
+    # Check first index level values
-
+    assert all(x == "bar" for x in index.levels[0].values)  # type: ignore
-    assert index.levels[1].name == "scan"
+    # Check first index level values shape
-    assert all(x == i for i, x in enumerate(index.levels[1].values))
+    assert index.levels[0].values.shape == (1,)  # type: ignore
-    assert index.levels[1].values.shape == (7,)
+    # Check second index level name
+    assert index.levels[1].name == "scan"  # type: ignore
+    # Check second index level values
+    assert all(
+        x == i for i, x in enumerate(index.levels[1].values)  # type: ignore
+    )
+    # Check second index level values shape
+    assert index.levels[1].values.shape == (7,)  # type: ignore
 
+    # Second element
     element = {"subject": "sub-01", "session": "ses-01"}
-    index = PandasBaseFeatureStorage.element_to_index(element, n_rows=10)
 
-    assert index.levels[0].name == "subject"
+    # Fifth test; default name for extra column and multi-level element access
-    assert all(x == "sub-01" for x in index.levels[0].values)
+    index = PandasBaseFeatureStorage.element_to_index(
-    assert index.levels[0].values.shape == (1,)
+        element=element, n_rows=10
-
+    )
-    assert index.levels[1].name == "session"
+    # Check first index level name
-    assert all(x == "ses-01" for x in index.levels[1].values)
+    assert index.levels[0].name == "subject"  # type: ignore
-    assert index.levels[1].values.shape == (1,)
+    # Check first index level values
-
+    assert all(x == "sub-01" for x in index.levels[0].values)  # type: ignore
-    assert index.levels[2].name == "idx"
+    # Check first index level values shape
-    assert all(x == i for i, x in enumerate(index.levels[2].values))
+    assert index.levels[0].values.shape == (1,)  # type: ignore
-    assert index.levels[2].values.shape == (10,)
+    # Check second index level name
+    assert index.levels[1].name == "session"  # type: ignore
+    # Check second index level values
+    assert all(x == "ses-01" for x in index.levels[1].values)  # type: ignore
+    # Check second index level values shape
+    assert index.levels[1].values.shape == (1,)  # type: ignore
+    # Check third index level name
+    assert index.levels[2].name == "idx"  # type: ignore
+    # Check third index level values
+    assert all(
+        x == i for i, x in enumerate(index.levels[2].values)  # type: ignore
+    )
+    # Check third index level values shape
+    assert index.levels[2].values.shape == (10,)  # type: ignore

junifer/storage/tests/test_sqlite.py

@@ -1,4 +1,4 @@
-"""Provide tests for sqlite."""
+"""Provide tests for SQLite storage interface."""
 
 # Authors: Federico Raimondo <f.raimondo@fz-juelich.de>
 #          Synchon Mandal <s.mandal@fz-juelich.de>
@@ -361,8 +361,8 @@ def test_store_metadata(tmp_path: Path) -> None:
     assert meta_md5 == feature_md5
 
 
-def test_store_table(tmp_path: Path) -> None:
+def test_store_vector(tmp_path: Path) -> None:
-    """Test table store.
+    """Test vector store.
 
     Parameters
     ----------
@@ -370,7 +370,7 @@ def test_store_table(tmp_path: Path) -> None:
         The path to the test directory.
 
     """
-    uri = tmp_path / "test_store_table.sqlite"
+    uri = tmp_path / "test_store_vector.sqlite"
     storage = SQLiteFeatureStorage(uri=uri)
     # Metadata to store
     element = {"subject": "test"}
@@ -389,60 +389,29 @@ def test_store_table(tmp_path: Path) -> None:
     )
 
     # Data to store
-    data = [
+    data = [[10, 20, 30, 40, 50]]
-        [1, 10],
+    col_names = ["f1", "f2", "f3", "f4", "f5"]
-        [2, 20],
-        [3, 30],
-        [4, 40],
-        [5, 50],
-    ]
     # Convert element to index
-    idx = storage.element_to_index(element, n_rows=5, rows_col_name="scan")
+    idx = storage.element_to_index(element=element)
     # Create dataframe
-    df = pd.DataFrame(data, columns=["f1", "f2"], index=idx)
+    df = pd.DataFrame(data=data, columns=col_names, index=idx)
 
     # Store table
-    storage.store_table(
+    storage.store_vector(
         meta_md5=meta_md5,
         element=element_to_store,
         data=data,
-        columns=["f1", "f2"],
+        col_names=col_names,
-        rows_col_name="scan",
     )
     # Read stored table
     c_df = _read_sql(
         table_name=f"meta_{meta_md5}",
         uri=uri.as_posix(),
-        index_col=["subject", "scan"],
+        index_col=["subject"],
     )
     # Check if dataframes are equal
     assert_frame_equal(df, c_df)
 
-    # New data to store
-    data_new = [[1, 10], [2, 20], [3, 300], [4, 40], [5, 50], [6, 600]]
-    # Convert element to index
-    idx_new = storage.element_to_index(element, n_rows=6, rows_col_name="scan")
-    # Create dataframe
-    df_new = pd.DataFrame(data_new, columns=["f1", "f2"], index=idx_new)
-    # Check warning
-    with pytest.warns(RuntimeWarning, match=r"Some rows"):
-        # Store table
-        storage.store_table(
-            meta_md5=meta_md5,
-            element=element_to_store,
-            data=data_new,
-            columns=["f1", "f2"],
-            rows_col_name="scan",
-        )
-    # Read stored table
-    c_df_new = _read_sql(
-        table_name=f"meta_{meta_md5}",
-        uri=uri.as_posix(),
-        index_col=["subject", "scan"],
-    )
-    # Check if dataframes are equal
-    assert_frame_equal(df_new, c_df_new)
-
 
 def test_store_matrix(tmp_path: Path) -> None:
     """Test matrix store.
@@ -453,7 +422,7 @@ def test_store_matrix(tmp_path: Path) -> None:
         The path to the test directory.
 
     """
-    uri = tmp_path / "test_store_table.sqlite"
+    uri = tmp_path / "test_store_matrix.sqlite"
     storage = SQLiteFeatureStorage(uri=uri)
     # Metadata to store
     element = {"subject": "test"}
@@ -478,7 +447,7 @@ def test_store_matrix(tmp_path: Path) -> None:
     row_names = ["row1", "row2", "row3", "row4"]
     col_names = ["col1", "col2", "col3"]
 
-    # Store table
+    # Store matrix
     storage.store_matrix(
         meta_md5=meta_md5,
         element=element_to_store,
@@ -497,13 +466,13 @@ def test_store_matrix(tmp_path: Path) -> None:
     assert_array_equal(read_df.values[0], data.flatten())
     assert list(read_df.columns) == stored_names
     # Store without row and column names
-    uri = tmp_path / "test_store_table_nonames.sqlite"
+    uri = tmp_path / "test_store_matrix_nonames.sqlite"
     storage = SQLiteFeatureStorage(uri=uri)
     # Store metadata
     storage.store_metadata(
         meta_md5=meta_md5, element=element_to_store, meta=meta_to_store
     )
-    # Store table
+    # Store matrix
     storage.store_matrix(
         meta_md5=meta_md5, element=element_to_store, data=data
     )
@@ -553,7 +522,7 @@ def test_store_matrix(tmp_path: Path) -> None:
     data = np.array([[1, 2, 3], [11, 22, 33], [111, 222, 333]])
     row_names = ["row1", "row2", "row3"]
     col_names = ["col1", "col2", "col3"]
-    uri = tmp_path / "test_store_table_triu.sqlite"
+    uri = tmp_path / "test_store_matrix_triu.sqlite"
     storage = SQLiteFeatureStorage(uri=uri)
     # Store metadata
     storage.store_metadata(
@@ -587,7 +556,7 @@ def test_store_matrix(tmp_path: Path) -> None:
     )
 
     # Store upper triangular matrix without diagonal
-    uri = tmp_path / "test_store_table_triu_nodiagonal.sqlite"
+    uri = tmp_path / "test_store_matrix_triu_nodiagonal.sqlite"
     storage = SQLiteFeatureStorage(uri=uri)
     # Store metadata
     storage.store_metadata(
@@ -622,7 +591,7 @@ def test_store_matrix(tmp_path: Path) -> None:
     data = np.array([[1, 2, 3], [11, 22, 33], [111, 222, 333]])
     row_names = ["row1", "row2", "row3"]
     col_names = ["col1", "col2", "col3"]
-    uri = tmp_path / "test_store_table_tril.sqlite"
+    uri = tmp_path / "test_store_matrix_tril.sqlite"
     storage = SQLiteFeatureStorage(uri=uri)
     # Store metadata
     storage.store_metadata(
@@ -656,7 +625,7 @@ def test_store_matrix(tmp_path: Path) -> None:
     )
 
     # Store lower triangular matrix without diagonal
-    uri = tmp_path / "test_store_table_tril_nodiagonal.sqlite"
+    uri = tmp_path / "test_store_matrix_tril_nodiagonal.sqlite"
     storage = SQLiteFeatureStorage(uri=uri)
     # Store metadata
     storage.store_metadata(
@@ -687,6 +656,60 @@ def test_store_matrix(tmp_path: Path) -> None:
     )
 
 
+def test_store_timeseries(tmp_path: Path) -> None:
+    """Test timeseries store.
+
+    Parameters
+    ----------
+    tmp_path : pathlib.Path
+        The path to the test directory.
+
+    """
+    uri = tmp_path / "test_store_timeseries.sqlite"
+    storage = SQLiteFeatureStorage(uri=uri)
+    # Metadata to store
+    element = {"subject": "test"}
+    dependencies = ["numpy"]
+    meta = {
+        "element": element,
+        "dependencies": dependencies,
+        "marker": {"name": "fc"},
+        "type": "BOLD",
+    }
+
+    meta_md5, meta_to_store, element_to_store = process_meta(meta)
+    # Store metadata
+    storage.store_metadata(
+        meta_md5=meta_md5, element=element_to_store, meta=meta_to_store
+    )
+
+    # Data to store
+    data = np.array([[10], [20], [30], [40], [50]])
+    col_names = ["signal"]
+    # Convert element to index
+    idx = storage.element_to_index(
+        element=element, n_rows=5, rows_col_name="timepoint"
+    )
+    # Create dataframe
+    df = pd.DataFrame(data=data, columns=col_names, index=idx)
+
+    # Store table
+    storage.store_timeseries(
+        meta_md5=meta_md5,
+        element=element_to_store,
+        data=data,
+        col_names=col_names,
+    )
+    # Read stored table
+    c_df = _read_sql(
+        table_name=f"meta_{meta_md5}",
+        uri=uri.as_posix(),
+        index_col=["subject", "timepoint"],
+    )
+    # Check if dataframes are equal
+    assert_frame_equal(df, c_df)
+
+
 # TODO: can the test be parametrized?
 def test_store_multiple_output(tmp_path: Path):
     """Test storing using single_output=False.
@@ -719,41 +742,28 @@ def test_store_multiple_output(tmp_path: Path):
         "type": "BOLD",
     }
     # Data to store
-    data1 = np.array(
+    data1 = np.array([[10, 20, 30, 40, 50]])
-        [
-            [1, 10],
-            [2, 20],
-            [3, 30],
-            [4, 40],
-            [5, 50],
-        ]
-    )
     data2 = data1 * 10
     data3 = data1 * 20
+    col_names = ["f1", "f2", "f3", "f4", "f5"]
     # Process metadata for storage
     hash1, meta_to_store1, element_to_store1 = process_meta(meta1)
     # Convert element to index
-    idx1 = storage.element_to_index(
+    idx1 = storage.element_to_index(element=element_to_store1)
-        element_to_store1, n_rows=5, rows_col_name="scan"
-    )
     # Create dataframe
-    df1 = pd.DataFrame(data1, columns=["f1", "f2"], index=idx1)
+    df1 = pd.DataFrame(data1, columns=col_names, index=idx1)
     # Process metadata for storage
     hash2, meta_to_store2, element_to_store2 = process_meta(meta2)
     # Convert element to index
-    idx2 = storage.element_to_index(
+    idx2 = storage.element_to_index(element=element_to_store2)
-        element_to_store2, n_rows=5, rows_col_name="scan"
-    )
     # Create dataframe
-    df2 = pd.DataFrame(data2, columns=["f1", "f2"], index=idx2)
+    df2 = pd.DataFrame(data2, columns=col_names, index=idx2)
     # Process metadata for storage
     hash3, meta_to_store3, element_to_store3 = process_meta(meta3)
     # Convert element to index
-    idx3 = storage.element_to_index(
+    idx3 = storage.element_to_index(element=element_to_store3)
-        element_to_store3, n_rows=5, rows_col_name="scan"
-    )
     # Create dataframe
-    df3 = pd.DataFrame(data3, columns=["f1", "f2"], index=idx3)
+    df3 = pd.DataFrame(data3, columns=col_names, index=idx3)
     # Check hash equality
     assert hash1 == hash2
     assert hash2 == hash3
@@ -767,26 +777,23 @@ def test_store_multiple_output(tmp_path: Path):
     storage.store_metadata(
         meta_md5=hash3, element=element_to_store3, meta=meta_to_store3
     )
-    storage.store_table(
+    storage.store_vector(
         meta_md5=hash1,
         element=element_to_store1,
         data=data1,
-        columns=["f1", "f2"],
+        col_names=col_names,
-        rows_col_name="scan",
     )
-    storage.store_table(
+    storage.store_vector(
         meta_md5=hash2,
         element=element_to_store2,
         data=data2,
-        columns=["f1", "f2"],
+        col_names=col_names,
-        rows_col_name="scan",
     )
-    storage.store_table(
+    storage.store_vector(
         meta_md5=hash3,
         element=element_to_store3,
         data=data3,
-        columns=["f1", "f2"],
+        col_names=col_names,
-        rows_col_name="scan",
     )
     # Check that URI does not exist yet
     assert not uri.exists()
@@ -803,12 +810,12 @@ def test_store_multiple_output(tmp_path: Path):
     assert uri2.exists()
     assert uri3.exists()
     # Set index columns
-    cols = ["subject", "session", "scan"]
+    idx_cols = ["subject", "session"]
     table_name = f"meta_{hash1}"
     # Read stored tables
-    cdf1 = _read_sql(table_name, uri1.as_posix(), index_col=cols)
+    cdf1 = _read_sql(table_name, uri1.as_posix(), index_col=idx_cols)
-    cdf2 = _read_sql(table_name, uri2.as_posix(), index_col=cols)
+    cdf2 = _read_sql(table_name, uri2.as_posix(), index_col=idx_cols)
-    cdf3 = _read_sql(table_name, uri3.as_posix(), index_col=cols)
+    cdf3 = _read_sql(table_name, uri3.as_posix(), index_col=idx_cols)
     # Check if dataframes are equal
     assert_frame_equal(df1, cdf1)
     assert_frame_equal(df2, cdf2)
@@ -871,26 +878,23 @@ def test_collect(tmp_path: Path) -> None:
     storage.store_metadata(
         meta_md5=hash3, element=element_to_store3, meta=meta_to_store3
     )
-    storage.store_table(
+    storage.store_vector(
         meta_md5=hash1,
         element=element_to_store1,
         data=data1,
-        columns=["f1", "f2"],
+        col_names=["f1", "f2"],
-        rows_col_name="scan",
     )
-    storage.store_table(
+    storage.store_vector(
         meta_md5=hash2,
         element=element_to_store2,
         data=data2,
-        columns=["f1", "f2"],
+        col_names=["f1", "f2"],
-        rows_col_name="scan",
     )
-    storage.store_table(
+    storage.store_vector(
         meta_md5=hash3,
         element=element_to_store3,
         data=data3,
-        columns=["f1", "f2"],
+        col_names=["f1", "f2"],
-        rows_col_name="scan",
     )
     # Convert element to prefix
     prefix1 = element_to_prefix(meta1["element"])
@@ -911,7 +915,7 @@ def test_collect(tmp_path: Path) -> None:
     # Check that URI exists now
     assert uri.exists()
     # Set index columns
-    cols = ["subject", "session", "scan"]
+    cols = ["subject", "session"]
     # Store metadata
     table_name = f"meta_{hash1}"
     # Read stored tables

junifer/storage/tests/test_storage_base.py

@@ -12,7 +12,9 @@ from junifer.storage.base import BaseFeatureStorage
 def test_BaseFeatureStorage_abstractness() -> None:
     """Test BaseFeatureStorage is abstract base class."""
     with pytest.raises(TypeError, match=r"abstract"):
-        BaseFeatureStorage(uri="/tm", storage_types=["matrix"])  # type: ignore
+        BaseFeatureStorage(
+            uri="/tmp", storage_types=["matrix"]  # type: ignore
+        )
 
 
 def test_BaseFeatureStorage() -> None:
@@ -21,8 +23,8 @@ def test_BaseFeatureStorage() -> None:
     class MyFeatureStorage(BaseFeatureStorage):
         """Implement concrete class."""
 
-        def __init__(self, uri, single_output=False):
+        def __init__(self, uri, single_output=True):
-            storage_types = ["matrix", "table", "timeseries"]
+            storage_types = ["matrix", "vector", "timeseries"]
             super().__init__(
                 uri=uri,
                 storage_types=storage_types,
@@ -30,7 +32,7 @@ def test_BaseFeatureStorage() -> None:
             )
 
         def get_valid_inputs(self):
-            return ["matrix", "table", "timeseries"]
+            return ["matrix", "vector", "timeseries"]
 
         def list_features(self):
             super().list_features()
@@ -48,7 +50,7 @@ def test_BaseFeatureStorage() -> None:
             return super().collect()
 
     # Check single_output is False
-    st = MyFeatureStorage(uri="/tmp")
+    st = MyFeatureStorage(uri="/tmp", single_output=False)
     assert st.single_output is False
     # Check single_output is True
     st = MyFeatureStorage(uri="/tmp", single_output=True)
@@ -66,11 +68,9 @@ def test_BaseFeatureStorage() -> None:
     with pytest.raises(NotImplementedError):
         st.read_df(None)
 
-    element = {"subject": "test"}
-    dependencies = ["numpy"]
     meta = {
-        "element": element,
+        "element": {"subject": "test"},
-        "dependencies": dependencies,
+        "dependencies": ["numpy"],
         "marker": {"name": "fc"},
         "type": "BOLD",
     }
@@ -88,7 +88,7 @@ def test_BaseFeatureStorage() -> None:
         st.store(kind="timeseries", meta=meta)
 
     with pytest.raises(NotImplementedError):
-        st.store(kind="table", meta=meta)
+        st.store(kind="vector", meta=meta)
 
     with pytest.raises(ValueError):
         st.store(kind="lego", meta=meta)

junifer/storage/utils.py

@@ -84,13 +84,13 @@ def process_meta(meta: Dict) -> Tuple[str, Dict, Dict]:
         The MD5 hash of the metadata.
     dict
         The processed metadata for storage.
-    tuple
+    dict
         The element.
 
     Raises
     ------
     ValueError
-        If `meta` is None or if it does not contain the key "element".
+        If ``meta`` is None or if it does not contain the key "element".
 
     """
     if meta is None:
@@ -98,7 +98,7 @@ def process_meta(meta: Dict) -> Tuple[str, Dict, Dict]:
     # Copy the metadata
     t_meta = meta.copy()
     # Remove key "element"
-    element = t_meta.pop("element", None)
+    element: Dict = t_meta.pop("element", None)
     if element is None:
         raise_error(msg="`meta` must contain the key 'element'")
     if "marker" not in t_meta: