code sample for pandas-dev#43351

Author: simonjayhawkins

bisect/43351.py

@@ -0,0 +1,42 @@
+# BUG: Inconsistent assignment of NAT values to datetime columns in MultiIndex #43351
+
+import numpy as np
+
+import pandas as pd
+
+print(pd.__version__)
+
+midx = pd.MultiIndex(
+    [
+        ["a", "b", "c"],
+        ["house", "store", "forest"],
+        ["clouds", "clear", "storm"],
+        ["fire", "smoke", "clear"],
+        [
+            np.datetime64("2001-01-01", "ns"),
+            np.datetime64("2002-01-01", "ns"),
+            np.datetime64("2003-01-01", "ns"),
+        ],
+        [1.0, np.nan, 2],
+    ],
+    [
+        [0, 0, 0, 0, 1, 1, 2],
+        [1, 1, 1, 1, 0, 0, 2],
+        [0, 0, 2, 2, 2, 0, 1],
+        [0, 0, 0, 1, 2, 0, 1],
+        [1, 0, 1, 2, 0, 0, 1],
+        [1, 0, 1, 2, 0, 0, 1],
+    ],
+)
+midx.names = ["alpha", "location", "weather", "sign", "timestamp", "float"]
+pdf = pd.DataFrame(
+    {"a": [1], "b": [2], "c": [3], "d": [2], "e": [0], "f": [2], "g": [10]}
+)
+pdf.columns = midx
+pdf["new_col"] = [11]
+
+result = pdf["new_col"]
+print(result)
+
+expected = pd.Series([11], dtype=np.int64, name="new_col")
+pd.testing.assert_series_equal(result, expected)