绘制右扩展水平线matplotlib

Question

我正在尝试使用matplotlib绘制右延伸的水平线，但我找不到我需要您帮助的方法。

1-我有一个带有日期，价格和指标值的熊猫df
2-我想在一张图表中绘制价格，将其绘制为一条线，并且在价格之上，我还要绘制一条扩展线，其中指标值高于阈值，预期结果类似于此图。

在第二张屏幕截图中，您可以看到价格线上的那些彩色圆圈，我想将其替换为水平的右延长线。 数据.csv：https://drive.google.com/open?id=1ncTTvwJXVeh6dMHrIML7MpjlS-Yfox_o

我正在尝试的代码段：

import pandas as pd 
import matplotlib.pyplot as plt

df = pd.read_csv('plot_data.csv')

BW121 = df[['BW121','Close']]
BW121 = BW121.where(BW121.BW121>70).dropna()

BW50=df[['BW50','Close']]
BW50 = BW50.where(BW50.BW50>70).dropna()

LW121 =df[['LW121','Close']]
LW121 = LW121.where(LW121.LW121>70).dropna()

LW50 = df[['LW50','Close']]
LW50 = LW50.where(LW50.LW50>70).dropna()

plt.style.use('fivethirtyeight')
plt.scatter(BW121.index,BW121['Close'], color ="green",label='BW121')
plt.scatter(BW50.index , BW50['Close'], color ="blue", s=80,label='BW50')

plt.scatter(LW121.index , LW121['Close'], color ="red", s=80,label='LW121')
plt.scatter(LW50.index , LW50['Close'], color ="orange", s=80,label='LW50')

#Price Plot
plt.plot(df.index, df['Close'], marker='',alpha = 0.5,color='green')

plt.legend(loc='upper right')
plt.show()

Answer 1

要在matplotlib中绘制水平线，可以使用plt.axhline：

plt.scatter(BW50['Close'], color="blue", label='BW50')

axhline具有xmin和xmax参数，如果您希望线条不要水平填充图的话。

根据您的特定结果，可以尝试：

import pandas as pd 
import matplotlib.pyplot as plt

df = pd.read_csv('plot_data.csv')

BW121 = df[['BW121','Close']]
BW121 = BW121.where(BW121.BW121>70).dropna()

BW50=df[['BW50','Close']]
BW50 = BW50.where(BW50.BW50>70).dropna()

LW121 =df[['LW121','Close']]
LW121 = LW121.where(LW121.LW121>70).dropna()

LW50 = df[['LW50','Close']]
LW50 = LW50.where(LW50.LW50>70).dropna()

plt.style.use('fivethirtyeight')
plt.scatter(BW121.index,BW121['Close'], color ="green",label='BW121')
plt.scatter(BW50.index , BW50['Close'], color ="blue", s=80,label='BW50')
# axhline used here, one for each 'Close' value
for i in BW50['Close']:
    plt.axhline(i, color ="blue", lw=0.5)

plt.scatter(LW121.index , LW121['Close'], color ="red", s=80,label='LW121')
plt.scatter(LW50.index , LW50['Close'], color ="orange", s=80,label='LW50')
# could repeat axhline here for other data etc.

#Price Plot
plt.plot(df.index, df['Close'], marker='',alpha = 0.5,color='green')

plt.legend(loc='upper right')
plt.show()