| 1278 | |
| 1279 | |
| 1280 | def test_isetitem(): |
| 1281 | df = DataFrame({"a": [1, 2, 3], "b": [4, 5, 6], "c": [7, 8, 9]}) |
| 1282 | df_orig = df.copy() |
| 1283 | df2 = df.copy(deep=False) # Trigger a CoW |
| 1284 | df2.isetitem(1, np.array([-1, -2, -3])) # This is inplace |
| 1285 | assert np.shares_memory(get_array(df, "c"), get_array(df2, "c")) |
| 1286 | assert np.shares_memory(get_array(df, "a"), get_array(df2, "a")) |
| 1287 | |
| 1288 | df2.loc[0, "a"] = 0 |
| 1289 | tm.assert_frame_equal(df, df_orig) # Original is unchanged |
| 1290 | assert np.shares_memory(get_array(df, "c"), get_array(df2, "c")) |
| 1291 | |
| 1292 | |
| 1293 | @pytest.mark.parametrize( |