Bug report

As opposed to dicts, pandas.DataFramse etc.name in container does not check if a field exists in a numpy array. Hence, mustn't doargs[1] in data unconditionally on the data type. This was spotted due to the indirectly related warning:

lib/matplotlib/tests/test_axes.py::test_structured_data  /home/travis/build/matplotlib/matplotlib/lib/matplotlib/axes/_axes.py:52: FutureWarning: elementwise == comparison failed and returning scalar instead; this will raise an error or perform elementwise comparison in the future.    if (not args[1] in data and

Possible fixes:

• Cleanup _plot_args_replacer logic #10872, which gets the logic straight
• or alternativelySimplify (quite a bit...) _preprocess_data #10928, which is a larger cleanup and removes_plot_args_replacer() altogether.