Half violin plot in matplotlib

Question

Recently matplotlib has added a native support for violin plot. What I want to do is half-violin plot as here. I guess that it can be done changing the body the function is returning. Do you know how to plot half violin plot as in the example but using the new function from matplotlib?

Answer 1

data1 = (np.random.normal(0, 1, size=10000), np.random.normal(0, 2, size=10000))
data2 = (np.random.normal(1, 1, size=10000), np.random.normal(1, 2, size=10000))

fig, ax = plt.subplots(figsize=(18, 7))

v1 = ax.violinplot(data1, points=100, positions=np.arange(0, len(data1)),
               showmeans=False, showextrema=False, showmedians=False)
for b in v1['bodies']:
    # get the center
    m = np.mean(b.get_paths()[0].vertices[:, 0])
    # modify the paths to not go further right than the center
    b.get_paths()[0].vertices[:, 0] = np.clip(b.get_paths()[0].vertices[:, 0], -np.inf, m)
    b.set_color('r')

v2 = ax.violinplot(data2, points=100, positions=np.arange(0, len(data2)), 
               showmeans=False, showextrema=False, showmedians=False)

for b in v2['bodies']:
    # get the center
    m = np.mean(b.get_paths()[0].vertices[:, 0])
    # modify the paths to not go further left than the center
    b.get_paths()[0].vertices[:, 0] = np.clip(b.get_paths()[0].vertices[:, 0], m, np.inf)
    b.set_color('b')

ax.legend([v1['bodies'][0],v2['bodies'][0]],['data1', 'data2'])