python - matplotlib.legend()函数用法解析

1.图例legend基础语法及用法

legend语法参数如下: matplotlib.pyplot.legend(*args, **kwargs)

 

 

 

 

 

 

 

(1)设置图例位置

使用loc参数

plt.legend(loc=\'lower left\')

0: ‘best\'

1: ‘upper right\'

2: ‘upper left\'

3: ‘lower left\'

4: ‘lower right\'

5: ‘right\'

6: ‘center left\'

7: ‘center right\'

8: ‘lower center\'

9: ‘upper center\'

10: ‘center\'

 

(2)设置图例字体

#设置字体大小

fontsize : int or float or {‘xx-small’, ‘x-small’, ‘small’, ‘medium’, ‘large’, ‘x-large’, ‘xx-large’}

 

(3)设置图例边框及背景

plt.legend(loc=\'best\',frameon=False) #去掉图例边框

plt.legend(loc=\'best\',edgecolor=\'blue\') #设置图例边框颜色

plt.legend(loc=\'best\',facecolor=\'blue\') #设置图例背景颜色,若无边框,参数无效

 

(4)设置图例标题

plt.legend(loc=\'best\',title=\'figure 1 legend\') #去掉图例边框

2.legend面向对象命令
(1)获取并设置legend图例
plt.legend(loc=0, numpoints=1)
leg = plt.gca().get_legend() #或leg=ax.get_legend()
ltext = leg.get_texts()
plt.setp(ltext, fontsize=12,fontweight=\'bold\')

(2)设置图例
legend = ax.legend((rectsTest1, rectsTest2, rectsTest3), (\'test1\', \'test2\', \'test3\'))
legend = ax.legend(loc=\'upper center\', shadow=True, fontsize=\'x-large\')
legend.get_frame().set_facecolor(\'red\') #设置图例legend背景为红色
frame = legend.get_frame()
frame.set_alpha(1)
frame.set_facecolor(\'none\') #设置图例legend背景透明

(3)移除图例
ax1.legend_.remove() ##移除子图ax1中的图例
ax2.legend_.remove() ##移除子图ax2中的图例
ax3.legend_.remove() ##移除子图ax3中的图例

3.案例：设置图例legend到图形边界外

#主要是bbox_to_anchor的使用

box = ax1.get_position()

ax1.set_position([box.x0, box.y0, box.width , box.height* 0.8])

ax1.legend(loc=\'center\', bbox_to_anchor=(0.5, 1.2),ncol=3)

 

 

4.案例：显示多图例legend

import matplotlib.pyplot as plt

import numpy as np

x = np.random.uniform(-1, 1, 4)

y = np.random.uniform(-1, 1, 4)

p1, = plt.plot([1,2,3])

p2, = plt.plot([3,2,1])

l1 = plt.legend([p2, p1], ["line 2", "line 1"], loc=\'upper left\')

p3 = plt.scatter(x[0:2], y[0:2], marker = \'D\', color=\'r\')

p4 = plt.scatter(x[2:], y[2:], marker = \'D\', color=\'g\')

# This removes l1 from the axes.

plt.legend([p3, p4], [\'label\', \'label1\'], loc=\'lower right\', scatterpoints=1)

# Add l1 as a separate artist to the axes

plt.gca().add_artist(l1)

 

 

 

 

import matplotlib.pyplot as plt

line1, = plt.plot([1,2,3], label="Line 1", linestyle=\'--\')

line2, = plt.plot([3,2,1], label="Line 2", linewidth=4)

# 为第一个线条创建图例

first_legend = plt.legend(handles=[line1], loc=1)

# 手动将图例添加到当前轴域

ax = plt.gca().add_artist(first_legend)

# 为第二个线条创建另一个图例

plt.legend(handles=[line2], loc=4)

plt.show()

 

 

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原文链接：https://blog.csdn.net/qq_33221533/article/details/81431264