绘制右延伸水平线 matplotlib

Question

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

1- 我有一个带有日期、价格和指标值的 pandas df
2-我想在一个图表中绘制价格作为一条线，并且在价格之上我想绘制一条延长线，其中我的指标值高于阈值，预期结果类似于这张图片。

第二个屏幕截图你可以看到价格线上的那些彩色圆圈我想用一条水平右延长线替换它们。 数据.csv：https://drive.google.com/open?id=1ncTTvwJXVeh6dMHrIML7MpjlS-Yfox_o

我正在尝试的代码 sn-p：

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 中绘制一条水平线，您可以使用plt.axhline：

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

axhline 有 xmin 和 xmax 参数，如果您不希望线条水平填充绘图。

根据您的具体结果，您可以尝试：

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()