implement coercion to namedlist

Author: jkanche

src/biocframe/frame.py

@@ -500,6 +500,22 @@ def get_data(self) -> Dict[str, Any]:
         """
         return self._data
 
+    def to_dict(self) -> Dict[str, Any]:
+        """Alias for :py:meth:`~get_data`.
+
+        Returns:
+            Dictionary of columns and their values.
+        """
+        return self.get_data()
+
+    def to_NamedList(self) -> ut.NamedList:
+        """Convert the ``BiocFrame`` to a :py:class:`~biocutils.NamedList`.
+
+        Returns:
+            A ``NamedList`` containing the columns.
+        """
+        return ut.NamedList([self._data[c] for c in self._column_names], names=self._column_names)
+
     @property
     def data(self) -> Dict[str, Any]:
         """Alias for :py:attr:`~get_data`."""
@@ -1127,6 +1143,12 @@ def set_columns(self, columns: Dict[Union[str, int], Any], in_place: bool = Fals
         previous = len(output._column_names)
 
         for column, value in columns.items():
+            if output.shape == (0, 0):
+                output._number_of_rows = ut.get_height(value)
+
+                if output._row_names is not None and len(output._row_names) == 0 and output._number_of_rows > 0:
+                    output._row_names = None
+
             if ut.get_height(value) != output.shape[0]:
                 raise ValueError(
                     "Length of `value`, does not match the number of the rows,"

tests/test_coercions.py

@@ -0,0 +1,34 @@
+import pytest
+from biocframe import BiocFrame
+import biocutils as ut
+
+def test_to_dict():
+    obj = BiocFrame({"A": [1, 2], "B": [3, 4]})
+    d = obj.to_dict()
+    
+    assert isinstance(d, dict)
+    assert d["A"] == [1, 2]
+    assert d["B"] == [3, 4]
+    assert d is obj.get_data()
+
+def test_to_NamedList():
+    obj = BiocFrame({"A": [1, 2], "B": [3, 4]})
+    
+    nl = obj.to_NamedList()
+    assert isinstance(nl, ut.NamedList)
+    assert len(nl) == 2
+    assert nl.get_names().as_list() == ["A", "B"]
+    assert nl[0] == [1, 2]
+    
+    # Test order
+    obj = BiocFrame({"B": [3, 4], "A": [1, 2]})
+    obj = obj.set_column_names(["B", "A"])
+    
+    obj2 = BiocFrame({}, column_names=[])
+    obj2["Z"] = [1]
+    obj2["X"] = [2]
+    
+    nl2 = obj2.to_NamedList()
+    assert nl2.get_names().as_list() == ["Z", "X"]
+    assert nl2[0] == [1]
+    assert nl2[1] == [2]