checkbox: add polars checkbox example

Feature request #1092

dev/docs/source/example_polars_checkbox.rst

@@ -0,0 +1,14 @@
+.. SPDX-License-Identifier: BSD-2-Clause
+   Copyright (c) 2013-2025, John McNamara, [email protected]
+
+.. _ex_polars_checkbox:
+
+Example: Polars Excel output with a boolean checkboxes
+======================================================
+
+A example of displaying the boolean values in a Polars dataframe as checkboxes
+in an output xlsx file.
+
+.. image:: _images/polars_checkbox.png
+
+.. literalinclude:: ../../../examples/polars_checkbox.py

dev/docs/source/polars_examples.rst

@@ -23,5 +23,6 @@ They show how to use XlsxWriter with `Polars <https://pola.rs/>`_ .
    example_polars_conditional.rst
    example_polars_format_default.rst
    example_polars_format_custom.rst
+   example_polars_checkbox.rst
    example_polars_sparklines.rst
 

dev/docs/source/worksheet.rst

@@ -1776,8 +1776,15 @@ checkbox with :func:`write_boolean` and a cell format that has the
 .. image:: _images/checkbox_boolean.png
 
 This latter method isn't required very often but it can be occasionally useful
-if you are dealing with boolean values in a dataframe.
+if you are dealing with boolean values in a dataframe:
 
+.. literalinclude:: ../../../examples/polars_checkbox.py
+   :lines: 11-
+
+.. image:: _images/polars_checkbox.png
+
+Note, this feature is currently possible with Pandas dataframes but it will be
+in a future release.
 
 worksheet.insert_button()
 -------------------------

examples/polars_checkbox.py

@@ -0,0 +1,31 @@
+##############################################################################
+#
+# A example of displaying the boolean values in a Polars dataframe as checkboxes
+# in an output xlsx file.
+#
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (c) 2013-2025, John McNamara, [email protected]
+#
+
+import polars as pl
+
+# Create a Pandas dataframe with some sample data.
+df = pl.DataFrame(
+    {
+        "Region": ["North", "South", "East", "West"],
+        "Target": [100, 70, 90, 120],
+        "On-track": [False, True, True, False],
+    }
+)
+
+# Write the dataframe to a new Excel file with formatting options.
+df.write_excel(
+    workbook="polars_checkbox.xlsx",
+    # Set the checkbox format for the "On-track" boolean column.
+    column_formats={"On-track": {"checkbox": True}},
+    # Set an alternative table style.
+    table_style="Table Style Light 9",
+    # Autofit the column widths.
+    autofit=True,
+)

xlsxwriter/worksheet.py

@@ -2937,9 +2937,8 @@ def conditional_format(
             options["criteria"] = criteria_type[options["criteria"]]
 
         # Convert boolean values if required.
-        if "value" in options:
-            if isinstance(options["value"], bool):
-                options["value"] = str(options["value"]).upper()
+        if "value" in options and isinstance(options["value"], bool):
+            options["value"] = str(options["value"]).upper()
 
         # Convert date/times value if required.
         if options["type"] in ("date", "time"):