Plotting Int64 columns with nulled integers (NAType) fails

[Khris777]

Code Sample, a copy-pastable example if possible

import pandas as pd
import numpy as np

df = pd.DataFrame({'A': [1, 2, 3, 4, 5], 'B': [7, 5, np.nan, 3, 2]})
df.plot(x='A', y='B')
df = df.astype('Int64')
df.plot(x='A', y='B')

Problem description

The first plotting command works, the second throws the error message

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

Expected Output

NAType should be treated the same way as numpy nan in plotting. Maybe transformed on the fly?

(I'm unsure if this is a pandas, a numpy, or a matplotlib issue, I'm starting here)

Output of pd.show_versions()

INSTALLED VERSIONS

commit : None
python : 3.7.6.final.0
python-bits : 64
OS : Windows
OS-release : 10
machine : AMD64
processor : Intel64 Family 6 Model 79 Stepping 1, GenuineIntel
byteorder : little
LC_ALL : None
LANG : en
LOCALE : None.None

pandas : 1.0.1
numpy : 1.18.1
pytz : 2019.3
dateutil : 2.8.1
pip : 20.0.2
setuptools : 45.2.0.post20200209
Cython : 0.29.15
pytest : None
hypothesis : None
sphinx : 2.4.1
blosc : None
feather : None
xlsxwriter : 1.2.7
lxml.etree : 4.5.0
html5lib : 1.0.1
pymysql : None
psycopg2 : None
jinja2 : 2.11.1
IPython : 7.12.0
pandas_datareader: None
bs4 : 4.8.2
bottleneck : None
fastparquet : 0.3.3
gcsfs : None
lxml.etree : 4.5.0
matplotlib : 3.1.3
numexpr : None
odfpy : None
openpyxl : 3.0.3
pandas_gbq : None
pyarrow : 0.16.0
pytables : None
pytest : None
pyxlsb : None
s3fs : None
scipy : 1.4.1
sqlalchemy : 1.3.13
tables : None
tabulate : None
xarray : None
xlrd : 1.2.0
xlwt : None
xlsxwriter : 1.2.7
numba : 0.48.0

[TomAugspurger]

Can you post the full traceback?

[Khris777]

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'

[jorisvandenbossche]

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

[jeandersonbc]

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 :)

[jorisvandenbossche]

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

[AnnaDaglis]

take