Python Scatter plot not working with “None” points

Question

Say I create three lists:

x=[1,2,3]
y=[4,5,6]
z=[1,None,4]

How can I scatter this and simply only include the points with numbers (ie exclude the "none" point). My code won't produce a scatter plot when I include these lists (however when I include a number instead of "None" it works):

from mpl_toolkits import mplot3d
from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt

%matplotlib notebook


fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')


ax.scatter(x, y, z, c='r', marker='o')



plt.show()

Answer 1

You can do

import numpy as np

and replace your None with a np.nan . The points containing np.nan will not be plotted in your scatter plot. See this matplotlib doc for more information.

If you have long lists containing None , you can perform the conversion via

array_containing_nans = np.array(list_containing_nones, dtype=float)

Answer 2

you can use numpy.nan instead of None

import numpy as np
z=[1,None,4]
z_numpy = np.asarray(z, dtype=np.float32)

.... 

ax.scatter(x, y, z_numpy, c='r', marker='o')

Answer 3

You should use NaNs instead of None which is not the same thing. A NaN is a float.

Minimal example

import numpy as np
import matplotlib.pyplot as plt

x=[1,2,3]
y=[4,5,6]
z=[1,np.nan,4]

plt.scatter(x,y,z)
plt.show()