Can you post the full traceback?

Gladly:

Traceback (most recent call last):

  File "C:\Users\My.Name\Documents\Python_Projects\GIT\miscellaneous\temp.py", line 14, in <module>
    df.plot(x='A', y='B')

  File "C:\Users\My.Name\AppData\Local\Continuum\miniconda3\envs\main\lib\site-packages\pandas\plotting\_core.py", line 847, in __call__
    return plot_backend.plot(data, kind=kind, **kwargs)

  File "C:\Users\My.Name\AppData\Local\Continuum\miniconda3\envs\main\lib\site-packages\pandas\plotting\_matplotlib\__init__.py", line 61, in plot
    plot_obj.generate()

  File "C:\Users\My.Name\AppData\Local\Continuum\miniconda3\envs\main\lib\site-packages\pandas\plotting\_matplotlib\core.py", line 263, in generate
    self._make_plot()

  File "C:\Users\My.Name\AppData\Local\Continuum\miniconda3\envs\main\lib\site-packages\pandas\plotting\_matplotlib\core.py", line 1085, in _make_plot
    **kwds,

  File "C:\Users\My.Name\AppData\Local\Continuum\miniconda3\envs\main\lib\site-packages\pandas\plotting\_matplotlib\core.py", line 1104, in _plot
    lines = MPLPlot._plot(ax, x, y_values, style=style, **kwds)

  File "C:\Users\My.Name\AppData\Local\Continuum\miniconda3\envs\main\lib\site-packages\pandas\plotting\_matplotlib\converter.py", line 66, in wrapper
    return func(*args, **kwargs)

  File "C:\Users\My.Name\AppData\Local\Continuum\miniconda3\envs\main\lib\site-packages\pandas\plotting\_matplotlib\core.py", line 656, in _plot
    return ax.plot(*args, **kwds)

  File "C:\Users\My.Name\AppData\Local\Continuum\miniconda3\envs\main\lib\site-packages\matplotlib\axes\_axes.py", line 1667, in plot
    self.add_line(line)

  File "C:\Users\My.Name\AppData\Local\Continuum\miniconda3\envs\main\lib\site-packages\matplotlib\axes\_base.py", line 1902, in add_line
    self._update_line_limits(line)

  File "C:\Users\My.Name\AppData\Local\Continuum\miniconda3\envs\main\lib\site-packages\matplotlib\axes\_base.py", line 1924, in _update_line_limits
    path = line.get_path()

  File "C:\Users\My.Name\AppData\Local\Continuum\miniconda3\envs\main\lib\site-packages\matplotlib\lines.py", line 1027, in get_path
    self.recache()

  File "C:\Users\My.Name\AppData\Local\Continuum\miniconda3\envs\main\lib\site-packages\matplotlib\lines.py", line 675, in recache
    y = _to_unmasked_float_array(yconv).ravel()

  File "C:\Users\My.Name\AppData\Local\Continuum\miniconda3\envs\main\lib\site-packages\matplotlib\cbook\__init__.py", line 1388, in _to_unmasked_float_array
    return np.ma.asarray(x, float).filled(np.nan)

  File "C:\Users\My.Name\AppData\Local\Continuum\miniconda3\envs\main\lib\site-packages\numpy\ma\core.py", line 7849, in asarray
    subok=False, order=order)

  File "C:\Users\My.Name\AppData\Local\Continuum\miniconda3\envs\main\lib\site-packages\numpy\ma\core.py", line 2795, in __new__
    order=order, subok=True, ndmin=ndmin)

TypeError: float() argument must be a string or a number, not 'NAType'

We need to convert to floats with NaNs before passing the data to matplotlib, I suppose.

Hi! Can I make an attempt on this one? I'm looking for issues that can be useful to the community and help me to understand better how pandas works in depth :)

@jeandersonbc yes, that's welcome!
If you have any questions, don't hesitate to ask

take

@AnnaDaglis someone else (@jeandersonbc) already just commented he would like to look at it, so I would first give him some time before taking this issue

Thanks @jorisvandenbossche, I didn't manage time to work on the issue since last time that I posted so that's why I didn't reply early.
As far as I can see, it is my understanding from your suggestion that there should be verification for NA values before calling plot_backend.plot(data, kind=kind, **kwargs), right? I'll be submitting a PR later today with some tests to see how it goes.

there should be verification for NA values before calling plot_backend.plot(data, kind=kind, **kwargs)

Yes, I think so. But the check might need to be done lower in the stack, as when calling plot_backend.plot(), data is still a dataframe. I think we can focus here on the matplotlib backend included in pandas, and thus we need to ensure converting to float dtype (with to_numpy(float, na_value=np.nan) if it is nullable integer dtype) before passing it to matplotlib's plot().

take

So, I approached the problem by checking the numerical data in _compute_plot_data from matplot's backend. all tests pass, but I wonder if more tests should be added (e.g., at "pandas/tests/plotting/test_frame.py"). Any thoughts? Thanks already!

Hi @AnnaDaglis - looks like the linked PR went stale (unfortunately), are you still interested in working on this?

take

I'm no longer working on this, as my minimal fix wasn't accepted and this might need a more structural solution for 3rd party lib operations on nullable types.

take