from pandas import Index import pandas._testing as tm def test_add_prefix_suffix(float_frame): with_prefix = float_frame.add_prefix("foo#") expected = Index([f"foo#{c}" for c in float_frame.columns]) tm.assert_index_equal(with_prefix.columns, expected) with_suffix = float_frame.add_suffix("#foo") expected = Index([f"{c}#foo" for c in float_frame.columns]) tm.assert_index_equal(with_suffix.columns, expected) with_pct_prefix = float_frame.add_prefix("%") expected = Index([f"%{c}" for c in float_frame.columns]) tm.assert_index_equal(with_pct_prefix.columns, expected) with_pct_suffix = float_frame.add_suffix("%") expected = Index([f"{c}%" for c in float_frame.columns]) tm.assert_index_equal(with_pct_suffix.columns, expected)