Adding labels to grouped violin plot matplotlib

Question

I have a plot of 3 groups of 3 violins (so 9 violin plots) on the same axis and I want to label the groups, here is my attempt:

ax = plt.violinplot([method1[:,0].flatten(),method2[:,0].flatten(),method3[:,0].flatten()],positions= [1,2,3],showmeans=True,showmedians=False)
ax = plt.violinplot([method1[:,1].flatten(),method2[:,1].flatten(),method3[:,1].flatten()],positions=[5,6,7],showmeans=True,showmedians=False)
ax = plt.violinplot([method1[:,2].flatten(),method2[:,2].flatten(),method3[:,2].flatten()],positions=[9,10,11],showmeans=True,showmedians=False)


#positions = (([1,2,3],[5,6,7],[9,10,11]))
#labels = ( "method 1", "method 2","method 3")
#plt.xticks(positions = [2,6,10], labels)

ax.set_xticklabels(['method 1','method 2','method 3'])
ax.set_xticks([2,6,10])

I get the violin plots as intended but I can't figure out how to add the labels correctly. I get the error:

module 'matplotlib.pyplot' has no attribute 'set_xticklabels'

Try this: `ax.xticks([2, 6, 10], labels=['method 1','method 2','method 3'])` — r-beginners, Mar 08 '22 at 12:43
Hi, what was the error with plt.xticks([2,6,10], ['method 1','method 2','method 3'])? I thought that should work. — Duca, Mar 08 '22 at 12:45
@duca It said ```positional argument follows keyword argument``` with square or round brackets and points to the comma before labels — Lizardinablizzard, Mar 08 '22 at 12:55
@r-beginners I get ```'dict' object has no attribute 'xticks'``` — Lizardinablizzard, Mar 08 '22 at 12:56
`ax.set_xticks([2,6,10], labels=['method 1','method 2','method 3'])` is collect. — r-beginners, Mar 08 '22 at 12:59
@r-beginners I still get ```'dict' object has no attribute 'set_xticks'``` Do I need another package? — Lizardinablizzard, Mar 08 '22 at 13:03
This method works when I only have 3 violins: ``` positions = (1, 2, 3) labels = ( "method 1", "method 2","method 3") plt.xticks(positions, labels)``` — Lizardinablizzard, Mar 08 '22 at 13:06
Oh, now it works with that when I change the numbers - thanks! — Lizardinablizzard, Mar 08 '22 at 13:08
A confusing problem is that you write `ax = plt.violinplot(....)`. Contrary to `sns.violinplot`, `plt.violinplot` doesn't return an `ax`, but a dictionary of the created graphical elements. You can do `ax = plt.gca()` to the "current ax". Or you can call `plt.xticks(...)` which directly works on the "current ax". — JohanC, Mar 08 '22 at 13:17

score 1 · Answer 1 · answered Mar 08 '22 at 13:11

1

positions = (2, 6, 10)
labels = ( "m1", "m2","m3")
plt.xticks(positions, labels)

answered Mar 08 '22 at 13:11

Lizardinablizzard

55
9

Adding labels to grouped violin plot matplotlib

1 Answers1