Allow pandas series as accessor to FloatAccessor (#208)

lonboard/traits.py

@@ -186,7 +186,6 @@ def __init__(
         super().__init__(*args, **kwargs)
         self.tag(sync=True, **COLOR_SERIALIZATION)
 
-    # TODO: subclass self.error so that `info` is actually printed?
     def validate(
         self, obj, value
     ) -> Union[Tuple[int, ...], List[int], pa.ChunkedArray, pa.FixedSizeListArray]:
@@ -279,6 +278,9 @@ class FloatAccessor(FixedErrorTraitType):
     - A numpy `ndarray` with a numeric data type. This will be casted to an array of
       data type [`np.float32`][numpy.float32]. Each value in the array will be used as
       the value for the object at the same row index.
+    - A pandas `Series` with a numeric data type. This will be casted to an array of
+      data type [`np.float32`][numpy.float32]. Each value in the array will be used as
+      the value for the object at the same row index.
     - A pyarrow [`FloatArray`][pyarrow.FloatArray], [`DoubleArray`][pyarrow.DoubleArray]
       or [`ChunkedArray`][pyarrow.ChunkedArray] containing either a `FloatArray` or
       `DoubleArray`. Each value in the array will be used as the value for the object at
@@ -299,11 +301,18 @@ def __init__(
         super().__init__(*args, **kwargs)
         self.tag(sync=True, **FLOAT_SERIALIZATION)
 
-    # TODO: subclass self.error so that `info` is actually printed?
     def validate(self, obj, value) -> Union[float, pa.ChunkedArray, pa.DoubleArray]:
         if isinstance(value, (int, float)):
             return float(value)
 
+        # pandas Series
+        if (
+            value.__class__.__module__.startswith("pandas")
+            and value.__class__.__name__ == "Series"
+        ):
+            # Cast pandas Series to numpy ndarray
+            value = np.asarray(value)
+
         if isinstance(value, np.ndarray):
             if not np.issubdtype(value.dtype, np.number):
                 self.error(obj, value, info="numeric dtype")

tests/test_traits.py

@@ -1,4 +1,5 @@
 import numpy as np
+import pandas as pd
 import pyarrow as pa
 import pytest
 from ipywidgets import Widget
@@ -133,6 +134,9 @@ def test_float_accessor_validation_type():
     FloatAccessorWidget(value=np.array([2, 3, 4]))
     FloatAccessorWidget(value=np.array([2, 3, 4], dtype=np.float32))
     FloatAccessorWidget(value=np.array([2, 3, 4], dtype=np.float64))
+    FloatAccessorWidget(value=pd.Series([2, 3, 4]))
+    FloatAccessorWidget(value=pd.Series([2, 3, 4], dtype=np.float32))
+    FloatAccessorWidget(value=pd.Series([2, 3, 4], dtype=np.float64))
 
     # Must be floating-point array type
     with pytest.raises(TraitError):