code sample for pandas-dev#48124

Author: simonjayhawkins

bisect/48124.py

@@ -0,0 +1,27 @@
+# BUG: using NamedTuples with .loc works only sometimes #48124
+
+
+import pandas as pd
+from collections import namedtuple
+
+print(pd.__version__)
+
+# A df with two level MutltiIndex
+df = pd.DataFrame(
+    index=pd.MultiIndex.from_product(
+        [["A", "B"], ["a", "b", "c"]], names=["first", "second"]
+    )
+)
+
+# complicated subset
+expected = df.loc[("A", ["a", "b"]), :]  # <- Works
+
+indexer_tuple = namedtuple("Indexer", df.index.names)
+
+# complicated subset with named tuple
+result = df.loc[indexer_tuple(first="A", second=["a", "b"]), :]  # <- DOES NOT WORK!
+# Raises:
+# InvalidIndexError: Indexer(first='A', second=['a', 'b'])
+print(result)
+
+pd.testing.assert_frame_equal(result, expected)