Matplotlib：如何从列表中绘制数据，添加两个 y 轴？

Question

我需要用 matplotlib 制作一些情节，但我很不擅长。我有五个 lists，每个包含 100 个值。它们的值因以下因素而异：

我希望能够从中生成两个 line-and-marker 图表：

第一个图涉及清单 1、2、3 和 4，并且有 两个 y 轴。列表 1、2 和 3 依赖于常规 y 轴，而列表 4 依赖于 添加的 y 轴，如下所示：

第二个必须仅绘制列表 4 和 5，但使用常规 y 轴。

在继续之前，我需要将每个 list 变成 numpy array 吗？无论如何，我没弄清楚如何用 matplotlib 进行绘图。任何帮助都感激不尽。谢谢！

Answer 1

你只需要制作一个twinx axes to plot list 4 on a separate y axis. You can see an example here。

这是一个简短的脚本，可以执行您想要的操作。在这种情况下无需转换为 numpy 数组。

import matplotlib.pyplot as plt

# Some sample lists
l1 = [0.7,0.8,0.8,0.9,0.8,0.7,0.6,0.9,1.0,0.9]
l2 = [0.2,0.3,0.1,0.0,0.2,0.1,0.3,0.1,0.2,0.1]
l3 = [0.4,0.6,0.4,0.5,0.4,0.5,0.6,0.4,0.5,0.4]

l4 = [78,87,77,65,89,98,74,94,85,73]
l5 = [16,44,14,55,34,36,76,54,43,32]

# Make a figure
fig = plt.figure()

# Make room for legend at bottom
fig.subplots_adjust(bottom=0.2)

# The axes for your lists 1-3
ax1 = fig.add_subplot(211)
# A twin axis for list 4. This shares the x axis, but has a separate y axis
ax2 = ax1.twinx()

# Plot lines 1-3
line1 = ax1.plot(l1,'bo-',label='list 1')
line2 = ax1.plot(l2,'go-',label='list 2')
line3 = ax1.plot(l3,'ro-',label='list 3')

# Plot line 4
line4 = ax2.plot(l4,'yo-',label='list 4')

# Some sensible y limits
ax1.set_ylim(0,1)
ax2.set_ylim(0,100)

# Your second subplot, for lists 4&5
ax3 = fig.add_subplot(212)

# Plot lines 4&5
ax3.plot(l4,'yo-',label='list 4')
line5 = ax3.plot(l5,'mo-',label='list 5')

# To get lines 1-5 on the same legend, we need to 
# gather all the lines together before calling legend
lines = line1+line2+line3+line4+line5
labels = [l.get_label() for l in lines]

# giving loc a tuple in axes-coords. ncol=5 for 5 columns
ax3.legend(lines, labels, loc=(0,-0.4), ncol=5)

ax3.set_xlabel('events')

# Display the figure
plt.show()

Answer 2

import matplotlib.pyplot as plt

l1 = [0.1,0.2,0.3,0.5,0.8,1.7,3.6,6.9,9.0,3.9]
l2 = [100,80,70,40,30,20,10,8,5,3]

fig = plt.figure()
fig.subplots_adjust(bottom=0.2)

ax1 = fig.add_subplot(211)
ax2 = ax1.twinx()

line1 = ax1.plot(l1,'bo-',label='list 1', color="blue")
line2 = ax2.plot(l2,'yo-',label='list 2', color="green")

ax1.set_xlabel('X-axis', color="red")

ax1.set_ylabel('Y1-axis', color="blue") 
ax2.set_ylabel('Y2-axis', color="green") 

plt.show()

Matplotlib：如何从列表中绘制数据，添加两个 y 轴？

Matplotlib: how to plot data from lists, adding two y-axes?

python

numpy

matplotlib

plot

multiple-axes