首先填写matplotlib图例的右栏

Question

嘿,我试图将一个图例放在一个情节上,这样它就不会模糊图形.

import numpy as np
import matplotlib.pyplot as plt

X = np.linspace(0,100,11)

plt.plot(X,-X, label='plot 1')
plt.plot(X,-2*X, label='plot 2')
plt.plot(X,-3*X, label='plot 3')

leg=plt.legend(ncol=2)
leg.get_frame().set_visible(False)

plt.show()

因此,在上面的最小工作示例中,我希望能够做的是将图例中的"plot 2"标签移动到右列,即直接在"plot 3"下面.

任何帮助将不胜感激,谢谢.

Answer 1

图例从左到右填充列。换句话说，如果你欺骗它相信还有另一条线（图例中没有任何文本或线条颜色），那么你可以填充“plot 3”下的空间。

import numpy as np
import matplotlib.pyplot as plt
from pylab import *

X = np.linspace(0,100,11)

plt.plot(X,-X, label='plot 1', color='red')
plt.plot(X,-2*X, label='plot 2', color='green')
plt.plot(X,-3*X, label='plot 3', color='blue')


line1 = Line2D(range(10), range(10), marker='', color="red")
line2 = Line2D(range(10), range(10), marker='',color="green")
line3 = Line2D(range(10), range(10), marker='', color="blue")
line4 = Line2D(range(10), range(10), marker='', color="white")
plt.legend((line1,line4, line3,line2),('plot1','','plot3','plot2'),numpoints=1, loc=4,ncol=2)

plt.show()

Answer 2

@cosmosis答案的不同实现.它可能更灵活.

import numpy as np
import matplotlib.pyplot as plt

X = np.linspace(0,100,11)

plt.plot(X,-X, label='plot 1', color='red')
plt.plot(X,-2*X, label='plot 2', color='green')
plt.plot(X,-3*X, label='plot 3', color='blue')

(lines, labels) = plt.gca().get_legend_handles_labels()
#it's safer to use linestyle='none' and marker='none' that setting the color to white
#should be invisible whatever is the background
lines.insert(1, plt.Line2D(X,X, linestyle='none', marker='none'))
labels.insert(1,'')

plt.legend(lines,labels,numpoints=1, loc=4,ncol=1)

plt.show()

另一个选项是在此处创建两个图例,然后在此处使用bbox_to_anchor关键字替换它们

(lines, labels) = plt.gca().get_legend_handles_labels()
leg1 = plt.legend(lines[:1], labels[:1], bbox_to_anchor=(0,0,0.8,1), loc=1)
leg2 = plt.legend(lines[1:], labels[1:], bbox_to_anchor=(0,0,1,1), loc=1)
gca().add_artist(leg1)

这样做我得到了 无需在其他对象上添加任何内容.