python – 在分组后使用mean和std绘制错误栏

2023年8月6日 285次阅读

我有以下数据帧：

                    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

如果想要绘制2条曲线(点误差),使用索引列“插入”作为X轴并将两条曲线区分为“质量”[好,差],我该怎么办？它们也应该是不同的颜色.

我有点卡住,我制作了各种各样的情节.

最佳答案 您可以循环遍历df.groupby(‘quality’)中的组,并在每个组上调用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()

《python – 在分组后使用mean和std绘制错误栏》

要使两个图显示在相同的轴上：

>创建自己的轴对象,ax.
>在每次调用group.plot时将ax参数设置为axes对象

它可能看起来像条形图更好：

# 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()

《python – 在分组后使用mean和std绘制错误栏》

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