)
7
time = np.arange(10
)
8
temp = np.random.random(10)*30
9
Swdown = np.random.random(10)*100-10
10
Rn = np.random.random(10)*100-10
12
fig =
plt.figure()
13
ax = fig.add_subplot(111
)
14
ax.plot(time, Swdown,
'
-
'
, label =
'
Swdown
'
)
15
ax.plot(time, Rn,
'
-
'
, label =
'
Rn
'
)
16
ax2 =
ax.twinx()
17
ax2.plot(time, temp,
'
-r
'
, label =
'
temp
'
)
18
ax.legend(loc=
0)
19
ax.grid()
20
ax.set_xlabel(
"
Time (h)
"
)
21
ax.set_ylabel(r
"
Radiation ($MJ\,m^{-2}\,d^{-1}$)
"
)
22
ax2.set_ylabel(r
"
Temperature ($^\circ$C)
"
)
23
ax2.set_ylim(0, 35
)
24
ax.set_ylim(-20,100
)
25
ax2.legend(loc=
0)
26
plt.savefig(
'
0.png
'
)
每个句柄对应一个图例。
2. 合并图例
1） 仅使用一个轴的legend()函数
1 # -*- coding: utf-8 -*-
2 import numpy as np
3 import matplotlib.pyplot as plt
4 from matplotlib import rc
5 rc('mathtext', default='regular')
7 time = np.arange(10)
8 temp = np.random.random(10)*30
9 Swdown = np.random.random(10)*100-10
10 Rn = np.random.random(10)*100-10
12 fig = plt.figure()
13 ax = fig.add_subplot(111)
15 lns1 = ax.plot(time, Swdown, '-', label = 'Swdown')
16 lns2 = ax.plot(time, Rn, '-', label = 'Rn')
17 ax2 = ax.twinx()
18 lns3 = ax2.plot(time, temp, '-r', label = 'temp')
20 # added these three lines
21 lns = lns1+lns2+lns3
22 labs = [l.get_label() for l in lns]
23 ax.legend(lns, labs, loc=0)
25 ax.grid()
26 ax.set_xlabel("Time (h)")
27 ax.set_ylabel(r"Radiation ($MJ\,m^{-2}\,d^{-1}$)")
28 ax2.set_ylabel(r"Temperature ($^\circ$C)")
29 ax2.set_ylim(0, 35)
30 ax.set_ylim(-20,100)
31 plt.savefig('0.png')
可以看到y1轴和y2轴的图例已经合并了
2）使用figure.legend()
1 # -*- coding: utf-8 -*-
2 import numpy as np
3 import matplotlib.pyplot as plt
5 x = np.linspace(0,10)
6 y = np.linspace(0,10)
7 z = np.sin(x/3)**2*98
9 fig = plt.figure()
10 ax = fig.add_subplot(111)
11 ax.plot(x,y, '-', label = 'Quantity 1')
13 ax2 = ax.twinx()
14 ax2.plot(x,z, '-r', label = 'Quantity 2')
15 fig.legend(loc=1)
17 ax.set_xlabel("x [units]")
18 ax.set_ylabel(r"Quantity 1")
19 ax2.set_ylabel(r"Quantity 2")
21 plt.savefig('0.png')
可以看到图例位置不对，已经出界，需要使用bbox_to_anchor和bbox_transform设置。
fig.legend(loc=1, bbox_to_anchor=(1,1), bbox_transform=ax.transAxes)
1 # -*- coding: utf-8 -*-
2 import numpy as np
3 import matplotlib.pyplot as plt
5 x = np.linspace(0,10)
6 y = np.linspace(0,10)
7 z = np.sin(x/3)**2*98
9 fig = plt.figure()
10 ax = fig.add_subplot(111)
11 ax.plot(x,y, '-', label = 'Quantity 1')
13 ax2 = ax.twinx()
14 ax2.plot(x,z, '-r', label = 'Quantity 2')
15 fig.legend(loc=1, bbox_to_anchor=(1,1), bbox_transform=ax.transAxes)
17 ax.set_xlabel("x [units]")
18 ax.set_ylabel(r"Quantity 1")
19 ax2.set_ylabel(r"Quantity 2")
21 plt.savefig('0.png')
可以看到图例已经正常了。
转自：
StackOverflow
