diff --git a/nvtabular/ops/categorify.py b/nvtabular/ops/categorify.py index 556e2a005a..ebdbc5e45f 100644 --- a/nvtabular/ops/categorify.py +++ b/nvtabular/ops/categorify.py @@ -1704,7 +1704,10 @@ def _encode( codes = type(df)({"order": dispatch.arange(len(df), like_df=df)}, index=df.index) for cl, cr in zip(selection_l.names, selection_r.names): - if isinstance(df[cl].dropna().iloc[0], (np.ndarray, list)): + column_without_nans = df[cl].dropna() + if len(column_without_nans) and isinstance( + column_without_nans.iloc[0], (np.ndarray, list) + ): ser = df[cl].copy() codes[cl] = dispatch.flatten_list_column_values(ser).astype(value[cr].dtype) else: diff --git a/tests/unit/ops/test_categorify.py b/tests/unit/ops/test_categorify.py index 41a69ef346..5092bb7fa7 100644 --- a/tests/unit/ops/test_categorify.py +++ b/tests/unit/ops/test_categorify.py @@ -734,3 +734,18 @@ def test_categorify_inference(): output_tensors = inference_op.transform(cats.input_columns, input_tensors) for key in input_tensors: assert output_tensors[key].dtype == np.dtype("int64") + + +def test_categorify_transform_only_nans_column(): + train_df = make_df({"cat_column": ["a", "a", "b", "c", np.nan]}) + cat_features = ["cat_column"] >> nvt.ops.Categorify() + train_dataset = nvt.Dataset(train_df) + + workflow = nvt.Workflow(cat_features) + workflow.fit(train_dataset) + + inference_df = make_df({"cat_column": [np.nan] * 10}) + inference_dataset = nvt.Dataset(inference_df) + + output = workflow.transform(inference_dataset).compute() + assert len(output) == len(inference_df)