我扩展了上面@Paul 的答案并使其更加健壮。它现在支持垂直和水平方向，我实现它以使用 inner='sticks' 因为这适合我的应用程序。
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.collections
import seaborn as sns
import pandas as pd
def offset_violinplot_halves(ax, delta, width, inner, direction):
"""
This function offsets the halves of a violinplot to compare tails
or to plot something else in between them. This is specifically designed
for violinplots by Seaborn that use the option `split=True`.
For lines, this works on the assumption that Seaborn plots everything with
integers as the center.
Args:
<ax> The axis that contains the violinplots.
<delta> The amount of space to put between the two halves of the violinplot
<width> The total width of the violinplot, as passed to sns.violinplot()
<inner> The type of inner in the seaborn
<direction> Orientation of violinplot. 'hotizontal' or 'vertical'.
Returns:
- NA, modifies the <ax> directly
"""
# offset stuff
if inner == 'sticks':
lines = ax.get_lines()
for line in lines:
if direction == 'horizontal':
data = line.get_ydata()
print(data)
if int(data[0] + 1)/int(data[1] + 1) < 1:
# type is top, move neg, direction backwards for horizontal
data -= delta
else:
# type is bottom, move pos, direction backward for hori
data += delta
line.set_ydata(data)
elif direction == 'vertical':
data = line.get_xdata()
print(data)
if int(data[0] + 1)/int(data[1] + 1) < 1:
# type is left, move neg
data -= delta
else:
# type is left, move pos
data += delta
line.set_xdata(data)
for ii, item in enumerate(ax.collections):
# axis contains PolyCollections and PathCollections
if isinstance(item, matplotlib.collections.PolyCollection):
# get path
path, = item.get_paths()
vertices = path.vertices
half_type = _wedge_dir(vertices, direction)
# shift x-coordinates of path
if half_type in ['top','bottom']:
if inner in ["sticks", None]:
if half_type == 'top': # -> up
vertices[:,1] -= delta
elif half_type == 'bottom': # -> down
vertices[:,1] += delta
elif half_type in ['left', 'right']:
if inner in ["sticks", None]:
if half_type == 'left': # -> left
vertices[:,0] -= delta
elif half_type == 'right': # -> down
vertices[:,0] += delta
def _wedge_dir(vertices, direction):
"""
Args:
<vertices> The vertices from matplotlib.collections.PolyCollection
<direction> Direction must be 'horizontal' or 'vertical' according to how
your plot is laid out.
Returns:
- a string in ['top', 'bottom', 'left', 'right'] that determines where the
half of the violinplot is relative to the center.
"""
if direction == 'horizontal':
result = (direction, len(set(vertices[1:5,1])) == 1)
elif direction == 'vertical':
result = (direction, len(set(vertices[-3:-1,0])) == 1)
outcome_key = {('horizontal', True): 'bottom',
('horizontal', False): 'top',
('vertical', True): 'left',
('vertical', False): 'right'}
# if the first couple x/y values after the start are the same, it
# is the input direction. If not, it is the opposite
return outcome_key[result]
# create some data
n = 100 # number of samples
c = ['cats', 'rats', 'bears', 'pears', 'snares'] # classes
y = np.random.randn(n)
x = np.random.choice(c, size=n)
z = np.random.rand(n) > 0.5 # sub-class
data = pd.DataFrame(dict(x=x, y=y, z=z))
print('done making data')
# initialise new axes;
fig, (ax1, ax2) = plt.subplots(2)
inner = "sticks" # Note: 'box' is default
width = 0.75
delta = 0.05
final_width = width - delta
print(data)
sns.violinplot(data=data, x='y', y='x',
split=True, hue = 'z',
ax = ax1, inner='sticks',
bw = 0.2)
sns.violinplot(data=data, x='x', y='y',
split=True, hue = 'z',
ax = ax2, inner='sticks',
bw = 0.2)
offset_violinplot_halves(ax1, delta, final_width, inner, 'horizontal')
offset_violinplot_halves(ax2, delta, final_width, inner, 'vertical')
plt.show()
