在循环内用空圆圈分散 plot

Question

I am looking for a simple and elegant way to make a scatter plot with multiple arrays, using empty circle as marker The colours should be chosen automatically. For example, I can make a plot with filled circle very easily:

a = {'1': np.random.rand(10), '2': np.random.rand(10), '3': np.random.rand(10)}
fig,ax = plt.subplots()
for y in ['2', '3']:
    ax.scatter(a[y], a['1'], label=y)

IF I want to use the kwargs facecolor="none" , the markers just disappear. Somehow I need to automatically assign colors to edgecolor

Answer 1

Assign the edge color manually via C0 , C1 , etc., which follow the default palette:

a = {'1': np.random.rand(10), '2': np.random.rand(10), '3': np.random.rand(10)}
fig,ax = plt.subplots()
for i, y in enumerate(['2', '3']):
    ax.scatter(a[y], a['1'], label=y, facecolor='none', edgecolor=f'C{i}')

Answer 2

You can also use string o as a marker :

a = {'1': np.random.rand(10), '2': np.random.rand(10), '3': np.random.rand(10)}
fig,ax = plt.subplots()
for y in ['2', '3']:
    ax.scatter(a[y], a['1'], label=y, marker='$o$')