python - Matplotlib:如何绘制列表中的数据，添加两个 y 轴？

Question

我需要用matplotlib生成一些图，但我对此很差。我有五个 列表，每个列表包含 100 值。它们的值因以下因素而异:

我希望能够生成两个line-and-marker图表:

1. 第一个图涉及列表 1、2、3 和 4，并具有两个 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，我需要将每个列表转换为numpy数组吗？不管怎样，我没能弄清楚如何使用 matplotlib 进行绘图。任何帮助都感激不尽。谢谢!

Answer 1

你只需要创建一个 twinx在单独的 y 轴上绘制 list 4 的坐标轴。你可以看一个例子here .

这是一个简短的脚本来完成您想要的操作。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()