pandas 使用 DataFrame.Plot 在同一图上绘制多个图
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/24227650/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Multiple plots on same figure with DataFrame.Plot
提问by Mark Graph
While I can get multiple lines on a chart and multiple bars on a chart - I cannot get a line and bar on the same chart using the same PeriodIndex.
虽然我可以在图表上获得多条线并在图表上获得多条柱线 - 但我无法使用相同的 PeriodIndex 在同一图表上获得线段和柱线。
Faux code follows ...
伪代码如下...
# play data
n = 100
x = pd.period_range('2001-01-01', periods=n, freq='M')
y1 = (Series(np.random.randn(n)).diff() + 5).tolist()
y2 = (Series(np.random.randn(n)).diff()).tolist()
df = pd.DataFrame({'bar':y2, 'line':y1}, index=x)
# let's plot
plt.figure()
ax = df['bar'].plot(kind='bar', label='bar')
df['line'].plot(kind='line', ax=ax, label='line')
plt.savefig('fred.png', dpi=200)
plt.close()
Any help will be greatly appreciated ...
任何帮助将不胜感激 ...
回答by HYRY
The problem is: bar plots don't use index values as x axis, but use range(0, n). You can use twiny()to create a second axes that share yaxis with the bar axes, and draw line curve in this second axes.
问题是：条形图不使用索引值作为 x 轴，而是使用range(0, n). 您可以使用twiny()创建与条形轴共享 yaxis 的第二个轴，并在第二个轴上绘制线曲线。
The most difficult thing is how to align x-axis ticks. Here we define the align function, which will align ax2.get_xlim()[0]with x1in ax1and ax2.get_xlim()[1]with x2in ax1:
最困难的是如何对齐 x 轴刻度。这里我们定义对齐功能，将调整ax2.get_xlim()[0]与x1中ax1和ax2.get_xlim()[1]用x2在ax1：
def align_xaxis(ax2, ax1, x1, x2):
"maps xlim of ax2 to x1 and x2 in ax1"
(x1, _), (x2, _) = ax2.transData.inverted().transform(ax1.transData.transform([[x1, 0], [x2, 0]]))
xs, xe = ax2.get_xlim()
k, b = np.polyfit([x1, x2], [xs, xe], 1)
ax2.set_xlim(xs*k+b, xe*k+b)
Here is the full code:
这是完整的代码：
from matplotlib import pyplot as plt
import pandas as pd
from pandas import Series
import numpy as np
n = 50
x = pd.period_range('2001-01-01', periods=n, freq='M')
y1 = (Series(np.random.randn(n)) + 5).tolist()
y2 = (Series(np.random.randn(n))).tolist()
df = pd.DataFrame({'bar':y2, 'line':y1}, index=x)
# let's plot
plt.figure(figsize=(20, 4))
ax1 = df['bar'].plot(kind='bar', label='bar')
ax2 = ax1.twiny()
df['line'].plot(kind='line', label='line', ax=ax2)
ax2.grid(color="red", axis="x")
def align_xaxis(ax2, ax1, x1, x2):
"maps xlim of ax2 to x1 and x2 in ax1"
(x1, _), (x2, _) = ax2.transData.inverted().transform(ax1.transData.transform([[x1, 0], [x2, 0]]))
xs, xe = ax2.get_xlim()
k, b = np.polyfit([x1, x2], [xs, xe], 1)
ax2.set_xlim(xs*k+b, xe*k+b)
align_xaxis(ax2, ax1, 0, n-1)
and the output:
和输出：
