Matplotlib：如何從列表中添加兩個 y 軸的 plot 數據？

Question

我需要用matplotlib制作一些圖，但我很不擅長。 我有五個lists ，每個列表包含100值。 它們的值因以下因素而異：

我希望能夠從中生成兩個line-and-marker圖：

1. 第一個 plot 涉及列表 1、2、3 和 4，並且有兩個 y 軸。 列表 1、2 和 3 依賴於常規 y 軸，而列表 4 依賴於添加的 y 軸，如下所示：

2. 第二個必須是 plot 僅列表 4 和 5，但具有常規 y 軸。

在繼續之前，我是否需要將每個list轉換為numpy array ？ 無論如何，我沒能弄清楚如何使用matplotlib進行繪圖。 任何幫助都感激不盡。 謝謝！

Answer 1

您只需要制作一個twinx軸即可在單獨的 y 軸上繪制list 4 。 您可以在此處查看示例。

這是一個簡短的腳本來做你想做的事。 在這種情況下無需轉換為numpy數組。

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()