如何将错误栏添加到Matplotlib线图？ [英] How to add Error Bar to Matplotlib line plot?

问题描述

我有以下用于绘制线图的数据集。该图以从数据中获得的值的平均值的形式获得。我想在该图中添加误差条，以显示标准偏差。我查找了不同的答案，但在大多数答案中，他们明确定义了 x 和 y ，但是在这里我计算直接从数据框中绘制图。如何向该图添加误差线？

数据框df

  UserId |日期| -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 | b 
 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

 徽章= [ A， B， C] 
 
用于徽章的徽章：
 res.iloc [：，2：]。mean（）。plot（kind ='line'，label = badge）
  

输出

I have the following dataset which I use to plot a line plot. The plot is obtained as the mean of values obtained from the data. I want to add error bars to this plot which shall show the standard deviation. I have looked up to different answers but in most of them they had defined x and y explicitly, but here I calculate the plot directly from the dataframe. How to add error bar to this plot?

Dataframe 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

Code

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

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

Output

EDIT (Plot for only one graph with Standard Deviation)

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())

Executing this code produces the following error:

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

解决方案

If you want to create your lines & error bars in the loop, you can use the plt.errorbar() as normal inside the loop, but using seaborn is a lot easier if you can get your data in the appropriate format.

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
    );

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