code sample for pandas-dev#46922

Author: simonjayhawkins

bisect/46922.py

@@ -0,0 +1,17 @@
+# BUG: Concatenation of None with numerical values no longer converts None to Nan. #46922
+
+import pandas as pd
+
+print(pd.__version__)
+
+df1 = pd.DataFrame({"A": [None], "B": [12.34]})
+df2 = pd.DataFrame({"A": [12.34], "B": [12.34]})
+
+result = pd.concat([df1, df2])
+print(result)
+print(result.dtypes)
+
+expected = pd.DataFrame(
+    {"A": [None, 12.34], "B": [12.34, 12.34]}, dtype=float, index=[0, 0]
+)
+pd.testing.assert_frame_equal(result, expected)