python列中每一行的颜色编码箱线图

Question

我想像this那样绘制，其中x轴具有As，Cr，Cd，Pb列的值，并且箱形图使用鱼列进行颜色编码。可能吗？我的数据（csv）：

fish,As,Cr,Cd,Pb
T. ilisha,0.023,0.002,0.039,0.004
G. chapra,0.224,0.011,0.048,0.005
M. vittatus,0.678,0.015,0.236,0.106
G. giuris,0.368,0.011,0.179,0.037
C. punctatus,0.274,0.016,0.124,0.035
M. armatus,0.461,0.015,0.476,0.039
P. ticto,0.437,0.021,0.533,0.048
S. cascasia,0.301,0.009,0.068,0.011
A. mola,0.454,0.016,0.179,0.065
H. fossilis,0.423,0.023,0.423,0.117
L.bata,0.295,0.019,0.287,0.039
W. attu,0.448,0.019,0.231,0.035

Answer 1

这里是一种根据每个元素创建箱形图的方法，并带有指示每个鱼的位置。

pd.melt用于创建数据框的“长格式”，便于seaborn处理。基本上会创建2个新列，其中一列具有元素名称，一列具有相应的值。每个原始行都会转换为4个新行。

from matplotlib import pyplot as plt
import pandas as pd
import seaborn as sns
from io import StringIO

df_data = StringIO('''fish,As,Cr,Cd,Pb
T. ilisha,0.023,0.002,0.039,0.004
G. chapra,0.224,0.011,0.048,0.005
M. vittatus,0.678,0.015,0.236,0.106
G. giuris,0.368,0.011,0.179,0.037
C. punctatus,0.274,0.016,0.124,0.035
M. armatus,0.461,0.015,0.476,0.039
P. ticto,0.437,0.021,0.533,0.048
S. cascasia,0.301,0.009,0.068,0.011
A. mola,0.454,0.016,0.179,0.065
H. fossilis,0.423,0.023,0.423,0.117
L.bata,0.295,0.019,0.287,0.039
W. attu,0.448,0.019,0.231,0.035''')
df = pd.read_csv(df_data)

df_long = pd.melt(df, 'fish', var_name='element', value_name='value')

sns.boxplot(x='element', y='value', palette=['lightgrey'], data=df_long, showfliers=False)
sns.scatterplot(x='element', y='value', hue='fish', palette='Set3', edgecolor='black', marker='D', data=df_long, zorder=3)
plt.show()

PS：为避免scatterplot的标记重叠，可以使用stripplot代替：

sns.stripplot(x='element', y='value', hue='fish', palette='Set3', linewidth=1, edgecolor='black', marker='D', data=df_long, zorder=3)

对于scatterplot（而不是stripplot），您可以为每条鱼使用不同的标记：

markers = ['o', 'v', '^', '8', '*', 'P', 'D', 'X', 's', 'p', '<', '>']
sns.scatterplot(x='element', y='value', hue='fish', palette='Set3', linewidth=1, edgecolor='black', markers=markers, data=df_long, zorder=3)