Matplotlib: scatter plot with colormaps for edgecolor but no facecolor

I want to have a scatter plot with colormap for edgecolors but no facecolors. When I use facecolor='None', it does not work.

import numpy as np
import matplotlib.pyplot as plt


N = 50
x = np.random.rand(N)
y = np.random.rand(N)
colors = np.random.rand(N)
area = np.pi * (15 * np.random.rand(N))**2  # 0 to 15 point radii

plt.scatter(x, y, s=area,c=colors,facecolors='None',cmap="gist_rainbow", alpha=0.5)
plt.show()

Any solution?

The c argument will affect facecolor and edgecolor simultaneouly, the arguments facecolor and edgecolor are hence ignored.

A solution would be not to use the c argument together with a colormap, but instead use facecolors and edgecolors alone. In this case facecolors can be set to "None" and edgecolors can be given a list of colors to use.

To create this list, the same colormap can be applied.

c = plt.cm.gist_rainbow(colors)
plt.scatter(x, y, s=area,facecolors="None", edgecolors=c, lw=1,alpha=0.5)

A complete example:

import numpy as np
import matplotlib.pyplot as plt

N = 50
x = np.random.rand(N)
y = np.random.rand(N)
colors = np.random.rand(N)
area = np.pi * (15 * np.random.rand(N))**2  # 0 to 15 point radii

c = plt.cm.gist_rainbow(colors)
plt.scatter(x, y, s=area,facecolors="None", edgecolors=c, lw=2,alpha=0.5)
plt.show()