使用 Pandas 的数据透视表，在末尾添加额外的行并进行减法计算

Question

I have a dataframe df, looks like below:

product    price

prod0       10
prod1       20
prod2       30
prod3       40         
cashback    30

I want to create a pivot table using panda, where margin will be "GrandTot" and extra row will be there at the end "with cashbak" how can I get an output like below?

col_name     price     GrandTot
Product
prod0         10         10
prod1         20         20
prod2         30         30
prod3         40         40
cashback      30         30
GrandTot      100        100
with cashbak  70         70 

Answer 1

Convert product to index and add new column by sum , also add GrandTot row with subtract cashback :

df = df.set_index('product')
df['GrandTot'] = df.sum(axis=1)
df.loc['GrandTot'] = df.sum().sub(df.loc['cashback'], fill_value=0)
df.loc['with cashbak'] = df.loc['GrandTot'].sub(df.loc['cashback'], fill_value=0)

print (df)
              price  GrandTot
product                      
prod0            10        10
prod1            20        20
prod2            30        30
prod3            40        40
cashback         30        30
GrandTot        100       100
with cashbak     70        70

But it seems more logic is add total sum to with cashbak :

df = df.set_index('product')
df['GrandTot'] = df.sum(axis=1)
sum = df.sum()
df.loc['GrandTot'] = sum.sub(df.loc['cashback'], fill_value=0)
df.loc['with cashbak'] = sum

print (df)
              price  GrandTot
product                      
prod0            10        10
prod1            20        20
prod2            30        30
prod3            40        40
cashback         30        30
GrandTot        100       100
with cashbak    130       130