在matplotlib/seaborn中将图例添加到箱线图中

Question

我是Python新手

我使用以下代码在matplotlib/seaborn中生成了一个箱线图（带有Swarmlot覆盖）。我现在想添加一个图例，它遵循每个方框的颜色方案。我在网上找到的许多解决方案似乎不适用于这种特殊类型的图（例如，仅适用于grouped boxplots）

当我尝试实现建议的代码here时，我收到了错误消息

非常感谢您的所有意见

# Import libraries and modules

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

# Set seaborn style.

sns.set(style="whitegrid", palette="colorblind")

# Load summary tidy data.

tidy = pd.read_csv('tidy.csv')

# Define plots for tidy data

fig, ax = plt.subplots(figsize=(10,6))
ax = sns.boxplot(x='header1', y='header2', data=tidy, order=["header1", "header2"])
ax = sns.swarmplot(x="header1", y="header2", data=tidy, color=".25", order=["header1", "header2"])
labels = [item.get_text() for item in ax.get_xticklabels()]
labels[0] = 'header1'
labels[1] = 'header2'
ax.set_xticklabels(labels)
ax.legend(loc='best')

我正在处理的数据的示例

Object,Metric,Length
MT1,B2A1,3.57675
MT1,B2A2,2.9474600000000004
MT1,B2A3,2.247772857142857
MT1,B2A4,3.754455
MT1,B2A5,2.716282
MT1,B2A6,2.91325
MT10,B2A1,3.34361
MT10,B2A2,2.889958333333333
MT10,B2A3,2.22087
MT10,B2A4,2.87669
MT10,B2A5,1.6745005555555557
MT12,B2A1,3.3938900000000003
MT12,B2A2,2.00601
MT12,B2A3,2.1720200000000003
MT12,B2A4,2.452923333333333

Answer 1

no handles with labels found to put in the legend错误是由于调用ax.legend()而您的两位艺术家（boxplot和Swarmlot）没有标签

sns.boxplot基于matplotlib在scatter上的boxplot和sns.swarmplot，所以您只需分别给它们一个labels和label参数

ax = sns.boxplot(..., labels=["Metric", "Length"])
ax = sns.swarmplot(..., label="something goes here")

或者，根据this的说法，您可以让seaborn部分保持不变，并摆弄：

handles, _ = ax.get_legend_handles_labels()          # Get the artists.
ax.legend(handles, ["label1", "label2"], loc="best") # Associate manually the artists to a label.