pandas-pivot table operation-pivot_table

import pandas as pd
import numpy as np
# 创建dataframe
d = {
    
    
    'Name':['Alisa','Bobby','Cathrine','Alisa','Bobby','Cathrine',
            'Alisa','Bobby','Cathrine','Alisa','Bobby','Cathrine'],
    
    'Semester':['Semester 1','Semester 1','Semester 1','Semester 1','Semester 1','Semester 1',
            'Semester 2','Semester 2','Semester 2','Semester 2','Semester 2','Semester 2'],
     
    'Subject':['Mathematics','Mathematics','Mathematics','Science','Science','Science',
               'Mathematics','Mathematics','Mathematics','Science','Science','Science'],
    'Score':[62,47,55,74,31,77,85,63,42,67,89,81]}
 
df = pd.DataFrame(d)
df

df.pivot_table(values='Score', index='Semester', columns='Subject', aggfunc=np.sum)

df.pivot_table(values='Score', index='Semester', columns='Subject', margins=True, aggfunc=np.sum)

df.pivot_table(values='Score', index='Semester', columns='Subject', aggfunc={
    
    'mean', 'max', 'min'})

# 加载数据
cars_df = pd.read_csv('../data/cars.csv')
cars_df.head()

# 比较不同年份的不同厂商的车，在电池方面的不同
cars_df.pivot_table(values='(kW)', index='YEAR', columns='Make')