Ignore showIndex when df is a Polars DataFrame

Author: mwouts

docs/changelog.md

@@ -1,6 +1,13 @@
 ITables ChangeLog
 =================
 
+2.4.5 (2025-08-21)
+------------------
+
+**Fixed**
+- The `showIndex` argument is now ignored when `df` is a Polars DataFrame ([#422](https://github.com/mwouts/itables/issues/422))
+
+
 2.4.4 (2025-07-07)
 ------------------
 

src/itables/javascript.py

@@ -347,12 +347,12 @@ def _evaluate_show_index(df, showIndex) -> bool:
     """
     We don't want to show trivial indices (RangeIndex with no name) on Pandas DataFrames.
     """
-    if showIndex != "auto":
-        return showIndex
     if df is None:
         return False
     if pl is not pd and isinstance(df, pl.DataFrame):
         return False
+    if showIndex != "auto":
+        return showIndex
     if isinstance(df, pd.DataFrame):
         return df.index.name is not None or not isinstance(df.index, pd.RangeIndex)
     if pd_style is not None and isinstance(df, pd_style.Styler):

src/itables/version.py

@@ -1,3 +1,3 @@
 """ITables' version number"""
 
-__version__ = "2.4.4"
+__version__ = "2.4.5"

tests/test_polars.py

@@ -1,7 +1,7 @@
 import pytest
 
 from itables import to_html_datatable
-from itables.javascript import datatables_rows
+from itables.javascript import datatables_rows, get_itable_arguments
 from itables.sample_dfs import (
     get_dict_of_polars_test_dfs,
     get_dict_of_polars_test_series,
@@ -53,3 +53,17 @@ def test_render_polars_struct():
         datatables_rows(df.select(pl.col("X").value_counts(sort=True)))
         == '[["{\\"C\\",3}"], ["{\\"A\\",2}"], ["{\\"B\\",1}"]]'
     )
+
+
+@pytest.mark.parametrize("show_index", ["auto", False, True])
+def test_show_index_has_no_effect_on_polars_dataframes(show_index):
+    df = pl.DataFrame(
+        {
+            "A": [1, 2, 3],
+            "B": [4, 5, 6],
+        }
+    )
+    assert (
+        get_itable_arguments(df, showIndex=show_index)["data_json"]
+        == "[[1, 4], [2, 5], [3, 6]]"
+    )