code sample for pandas-dev#40662

Author: simonjayhawkins

bisect/40662.py

@@ -0,0 +1,17 @@
+# BUG: numpy functions (eg, np.add) on DataFrames with 'out' parameter no longer work properly #40662
+
+import numpy as np
+import pandas as pd
+
+print(pd.__version__)
+
+# doesn't work. bar remains an array of zeros
+foo = np.array([1, 2, 3, 4]).reshape(2, 2)
+df = pd.DataFrame(foo)
+bar = np.zeros_like(df)
+print(bar)
+result = np.add(df, 1, out=bar)
+print(bar)
+
+expected = np.array([[2, 3], [4, 5]])
+np.testing.assert_equal(bar, expected)