绘制errorbar均值和std分组后

Question

我有以下数据框：

    mean  std 
insert quality      
0.0 good  0.009905 0.003662 
0.1 good  0.450190 0.281895 
     poor  0.376818 0.306806 
0.2 good  0.801856 0.243288 
     poor  0.643859 0.322378 
0.3 good  0.833235 0.172025 
     poor  0.698972 0.263266 
0.4 good  0.842288 0.141925 
     poor  0.706708 0.241269 
0.5 good  0.853634 0.118604 
     poor  0.685716 0.208073 
0.6 good  0.845496 0.118609 
     poor  0.675907 0.207755 
0.7 good  0.826335 0.133820 
     poor  0.656934 0.222823 
0.8 good  0.829707 0.130154 
     poor  0.627111 0.213046 
0.9 good  0.816636 0.137371 
     poor  0.589331 0.232756 
1.0 good  0.801211 0.147864 
     poor  0.554589 0.245867 

，我应该怎么做，如果想使用作为X轴的索引列"Insert"和差异绘制两条曲线（点+错误）两条曲线按"Quality" [好，差]？它们也应该具有不同的颜色。

我有点卡住了，我制作了每一种情节，除了我需要的情节。

Answer 1

您可以遍历df.groupby('quality')中的组并在每个组上呼叫group.plot。

import numpy as np 
import pandas as pd 
import matplotlib.pyplot as plt 

df = pd.DataFrame({ 
    'insert': [0.0, 0.1, 0.1, 0.2, 0.2, 0.3, 0.3, 0.4, 0.4, 0.5, 0.5, 0.6, 0.6, 
    0.7, 0.7, 0.8, 0.8, 0.9, 0.9, 1.0, 1.0], 
    'mean': [0.009905, 0.45019, 0.376818, 0.801856, 0.643859, 0.833235, 
    0.698972, 0.842288, 0.706708, 0.853634, 0.685716, 0.845496, 0.675907, 
    0.826335, 0.656934, 0.829707, 0.627111, 0.816636, 0.589331, 0.801211, 
    0.554589], 
    'quality': ['good', 'good', 'poor', 'good', 'poor', 'good', 'poor', 'good', 
    'poor', 'good', 'poor', 'good', 'poor', 'good', 'poor', 'good', 'poor', 
    'good', 'poor', 'good', 'poor'], 
    'std': [0.003662, 0.281895, 0.306806, 0.243288, 0.322378, 0.172025, 
    0.263266, 0.141925, 0.241269, 0.118604, 0.208073, 0.118609, 0.207755, 
    0.13382, 0.222823, 0.130154, 0.213046, 0.137371, 0.232756, 0.147864, 
    0.245867]}) 

fig, ax = plt.subplots() # 1 

for key, group in df.groupby('quality'): 
    group.plot('insert', 'mean', yerr='std', label=key, ax=ax) # 2 

plt.show() 

为了使这两个地块出现在同一坐标：

1. 创建自己的axes对象，斧。
2. 设置ax参数，在每个呼叫的axes对象group.plot

---

它可能看起来像柱状图更好：

# fill in missing data with 0, so the bar plots are aligned 
df = df.pivot(index='insert', columns='quality').fillna(0).stack().reset_index() 

colors = ['green', 'red'] 
positions = [0, 1] 

for group, color, pos in zip(df.groupby('quality'), colors, positions): 
    key, group = group 
    print(group) 
    group.plot('insert', 'mean', yerr='std', kind='bar', width=0.4, label=key, 
       position=pos, color=color, alpha=0.5, ax=ax) 

ax.set_xlim(-1, 11) 
plt.show()