如何按条形图中的条形图按升序排序？

Question

I created a bar plot using matplotlib.pyplot and seaborn libraries. How can I sort bars in increasing order according to Speed ? I want to see the bars with the lowest speed on the left and the highest speed on the right.

df =
    Id         Speed
    1          30
    1          35 
    1          31
    2          20
    2          25
    3          80

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

%matplotlib inline

result = df.groupby(["Id"])['Speed'].aggregate(np.median).reset_index()

norm = plt.Normalize(df["Speed"].values.min(), df["Speed"].values.max())
colors = plt.cm.Reds(norm(df["Speed"])) 

plt.figure(figsize=(12,8))
sns.barplot(x="Id", y="Speed", data=gr_vel_1, palette=colors)
plt.ylabel('Speed', fontsize=12)
plt.xlabel('Id', fontsize=12)
plt.xticks(rotation='vertical')
plt.show()

Answer 1

df.groupby(['Id']).median().sort_values("Speed").plot.bar()

Or just try to sort_values("Speed") after you aggregate them.

EDIT: so you need to do this:

result = a.groupby(["Id"])['Speed'].aggregate(np.median).reset_index().sort_values('Speed')

and in sns.barplot add order:

sns.barplot(x='Id', y="Speed", data=a, palette=colors, order=result['Id'])