python groupby agg_python groupby agg()

構造資料

import pandas as pd

df = pd.DataFrame({'Country':['China','China', 'India', 'India', 'America', 'Japan', 'China', 'India'],

'Income':[10000, 10000, 5000, 5002, 40000, 50000, 8000, 5000],

'Age':[5000, 4321, 1234, 4010, 250, 250, 4500, 4321]})

結果如下：

Age Country Income

0 5000 China 10000

1 4321 China 10000

2 1234 India 5000

3 4010 India 5002

4 250 America 40000

5 250 Japan 50000

6 4500 China 8000

7 4321 India 5000

單列分組

df_gb = df.groupby('Country')

for index, data in df_gb:

print(index)

print(data)

輸出

America

Age Country Income

4 250 America 40000

China

Age Country Income

0 5000 China 10000

1 4321 China 10000

6 4500 China 8000

India

Age Country Income

2 1234 India 5000

3 4010 India 5002

7 4321 India 5000

Japan

Age Country Income

5 250 Japan 50000

多列分組

df_gb = df.groupby(['Country', 'Income'])

for (index1, index2), data in df_gb:

print((index1, index2))

print(data)

輸出

('America', 40000)

Age Country Income

4 250 America 40000

('China', 8000)

Age Country Income

6 4500 China 8000

('China', 10000)

Age Country Income

0 5000 China 10000

1 4321 China 10000

('India', 5000)

Age Country Income

2 1234 India 5000

7 4321 India 5000

('India', 5002)

Age Country Income

3 4010 India 5002

('Japan', 50000)

Age Country Income

5 250 Japan 50000

聚合函數，對分組後資料進行聚合

df_agg = df.groupby('Country').agg(['min', 'mean', 'max'])

print(df_agg)

輸出

Age Income

min mean max min mean max

Country

America 250 250.000000 250 40000 40000.000000 40000

China 4321 4607.000000 5000 8000 9333.333333 10000

India 1234 3188.333333 4321 5000 5000.666667 5002

Japan 250 250.000000 250 50000 50000.000000 50000

對分組後的部分列進行聚合

num_agg = {'Age':['min', 'mean', 'max']}

print(df.groupby('Country').agg(num_agg))

輸出

Age

min mean max

Country

America 250 250.000000 250

China 4321 4607.000000 5000

India 1234 3188.333333 4321

Japan 250 250.000000 250

num_agg = {'Age':['min', 'mean', 'max'], 'Income':['min', 'max']}

print(df.groupby('Country').agg(num_agg))

輸出

Age Income

min mean max min max

Country

America 250 250.000000 250 40000 40000

China 4321 4607.000000 5000 8000 10000

India 1234 3188.333333 4321 5000 5002

Japan 250 250.000000 250 50000 50000