When using the typical 3D plot like so:
from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt
fig = plt.figure()
ax = fig.gca(projection='3d')
flake8 reports the expected error:
./tools.py:62:9: F401 'mpl_toolkits.mplot3d.Axes3D' imported but unused
I know it can be avoided using the # NOQA comment. But is there a different way to formulate the projection in the figure so that the Axes3D object is used?
If this is only about actually using the import at least once, you can do
ax = fig.gca(projection=Axes3D.name)
as "3d" is the name of the Axes3D class by which it is registered to the projection list.
来源：https://stackoverflow.com/questions/42962613/how-to-directly-use-axes3d-from-matplotlib-in-standard-plot-to-avoid-flake8-erro