如何将误差线添加到 Matplotlib 线图

Question

我有以下数据集，用于绘制线图。该图是作为从数据中获得的值的mean 获得的。我想在该图中添加误差线，以显示标准偏差。我查看了不同的答案，但在大多数答案中，他们明确定义了x 和y，但在这里我直接从数据框中计算图。如何在该图中添加误差线？

数据框 df

UserId     |   date                 |-7|-6|-5|-4|-3|-2|-1|0 |1 |2 |3 |4 |5 |6 |7
     1      2009-10-17 17:38:32.590 |0 |0 |0 |0 |0 |0 |1 |0 |1 |0 |0 |0 |0 |0 |0  
     2      2009-10-19 00:37:23.067 |0 |0 |0 |0 |0 |1 |1 |0 |1 |0 |0 |0 |0 |0 |0    
     3      2009-10-20 08:37:14.143 |0 |0 |0 |0 |0 |0 |1 |0 |0 |0 |0 |0 |0 |0 |0 
     4      2009-10-21 18:07:51.247 |0 |0 |0 |0 |0 |0 |1 |0 |0 |0 |0 |0 |0 |0 |0 
     5      2009-10-22 21:25:24.483 |0 |0 |0 |0 |0 |0 |1 |0 |0 |0 |0 |0 |0 |0 |0

代码

badges = ["A", "B", "C"]

for badge in badges:
  res.iloc[:,2:].mean().plot(kind='line', label = badge)

输出

编辑（仅绘制一个具有标准偏差的图）

res.iloc[:,2:].mean().plot(kind='line', label = 'A')
plt.errorbar(x = res.columns.values[:-1], y = res.iloc[:,2:].mean(),yerr = res.iloc[:,2:].std())

执行此代码会产生以下错误：

TypeError: 'value' must be an instance of str or bytes, not a int

Answer 1

如果您想在循环中创建行和错误栏，您可以在循环中正常使用plt.errorbar()，但如果您可以以适当的格式获取数据，使用seaborn 会容易得多。

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

df = pd.concat([
    pd.DataFrame(np.random.randint(0,2, (5, 14))).assign(badge="A"),
    pd.DataFrame(np.random.randint(0,2, (5, 14))).assign(badge="B"),
])

plt.figure(figsize=(10, 5))

badges = ["A", "B"]
colors = ["teal", "firebrick"]

for i, badge in enumerate(badges):
    
    sub_df = df[df["badge"]==badge]
    
    sub_df.iloc[:,:-1].mean().plot(kind='line', label=badge, color=colors[i])

    plt.errorbar(
        sub_df.columns.values[:-1] + (i*0.1), # offset the second error bar a bit
        sub_df.iloc[:,:-1].mean(),
        yerr=sub_df.iloc[:,:-1].std(),
        fmt='|', ecolor='grey', elinewidth=1
    );