code sample for pandas-dev#47501

Author: simonjayhawkins

bisect/47501.py

@@ -0,0 +1,12 @@
+# PERF: concat along axis 1 unnecessarily materializes RangeIndex->Int64Index #47501
+
+import pandas as pd
+
+print(pd.__version__)
+
+result = pd.concat(
+    [pd.DataFrame({"a": range(10)}), pd.DataFrame({"b": range(10)})], sort=True, axis=1
+)
+print(result.index)
+
+assert isinstance(result.index, pd.RangeIndex)