在 Matplotlib 图中注释来自 Pandas 数据框的点
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Annotating points from a Pandas Dataframe in Matplotlib plot
提问by dartdog
Given a DataFramelike:
给出一个DataFrame喜欢：
LIST_PRICE SOLD_PRICE
MOYRLD
1999-03-31 317062.500000 314800
1999-06-30 320900.000000 307100
1999-09-30 400616.666667 366160
1999-12-31 359900.000000 NaN
2000-03-31 359785.714286 330750
Using the code:
使用代码：
import matplotlib.dates as mdates
ax3=df5.plot()
ax3.set_ylim(100000,600000)
ax3.set_title('Heatherwood-Quarterly')
I generate a plot like:
我生成一个情节，如：
I cannot figure out how to get the axis to attach an annotation?
This example Annotate Time Series plot in Matplotlibis very close but I don't know how to specify the x and y axis from the DataFrame?
我不知道如何让轴附加注释？这个示例在 Matplotlib 中注释时间序列图非常接近，但我不知道如何从DataFrame?
So it should be close to:
所以它应该接近：
ax3.annotate('Test', (mdates.date2num(x[1]), y[1]), xytext=(15, 15),
textcoords='offset points', arrowprops=dict(arrowstyle='-|>'))
fig.autofmt_xdate()
plt.show()
But what do I use instead of x[1]and y[1]to get the axis? I tried ['MORLD'][1]and ['SOLD_PRICE'][1]and got index out of range...
但是我用什么代替x[1]andy[1]来获取轴？我试过['MORLD'][1]和['SOLD_PRICE'][1]，得到了 index out of range...
回答by sodd
You can access the index values with the indexattribute of the DataFrame. So you can simply use
您可以使用 的index属性访问索引值DataFrame。所以你可以简单地使用
ax3.annotate('Test',
(df5.index[1], df5['SOLD_PRICE'][1]),
xytext=(15, 15),
textcoords='offset points',
arrowprops=dict(arrowstyle='-|>'))
This gives (based on your sample data) the below output:
这给出（基于您的示例数据）以下输出：
