code sample for pandas-dev#45818

Author: simonjayhawkins

bisect/45818.py

@@ -0,0 +1,18 @@
+# BUG: Using .loc with DatetimeIndex drops index name #45818
+
+import pandas as pd
+
+print(pd.__version__)
+
+x = pd.DataFrame(
+    {"y": [1, 2, 3]}, index=pd.DatetimeIndex(["2020-01-01", "2020-01-02", "2020-01-03"])
+)
+x.index.names = ["abc"]
+
+idx = pd.DatetimeIndex(["2020-01-01"])
+result = x.loc[idx]
+print(result)
+
+# expected = pd.DataFrame({"y": [1]}, index=idx)
+# pd.testing.assert_frame_equal(result, expected)
+assert result.index.name == "abc"