如何找出每种产品在 Pandas DataFrame 中的销量

Question

我有一个像这样的熊猫数据框：

      Name Product  Amount
0      Bob   Apple       1
1      Bob  Banana       2
2  Jessica  Orange       3
3  Jessica  Banana       4
4  Jessica  Tomato       3
5     Mary  Banana       2
6     John   Apple       3
7     John   Grape       1

import pandas as pd

data = [('Bob','Apple',1), ('Bob','Banana',2), ('Jessica','Orange',3),
      ('Jessica','Banana',4),('Jessica','Tomato',3), ('Mary','Banana',2),
      ('John','Apple',3),('John','Grape',1)]

df = pd.DataFrame(data,columns=['Name','Product','Amount'])

到目前为止我所做的：

l = []
count=0
for i in range(0,8):
    row = df.iloc[i]
    
    if row.Product not in l:
        l.append(row.Product)

现在，l包含“产品”列中的所有唯一值，但我还需要总金额。

我如何查明每种产品的销量（例如，售出 4 件 Apple）？

Answer 1

您正在寻找.groupby()功能：

print( df.groupby('Product')['Amount'].sum() )

印刷：

Product
Apple     4
Banana    8
Grape     1
Orange    3
Tomato    3
Name: Amount, dtype: int64

out = df.groupby('Product')['Amount'].sum()
print('{} units of Apple were sold.'.format(out.loc['Apple']))

印刷：

4 of Apple were sold.