繪製errorbar均值和std分組後

Question

我有以下數據框：

    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 

，我應該怎麼做，如果想使用作爲X軸的索引列"Insert"和差異繪製兩條曲線（點+錯誤）兩條曲線按"Quality" [好，差]？它們也應該具有不同的顏色。

我有點卡住了，我製作了每一種情節，除了我需要的情節。

Answer 1

您可以遍歷df.groupby('quality')中的組並在每個組上呼叫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() 

爲了使這兩個地塊出現在同一座標：

1. 創建自己的axes對象，斧。
2. 設置ax參數，在每個呼叫的axes對象group.plot

---

它可能看起來像柱狀圖更好：

# 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()