使用dataframe中的groupby执行数据过滤和逐个元素的减法

import pandas as pd

# 创建一个示例dataframe
data = {'A': ['foo', 'bar', 'foo', 'bar', 'foo', 'bar', 'foo', 'foo'],
        'B': ['one', 'one', 'two', 'two', 'two', 'one', 'two', 'one'],
        'C': [1, 2, 3, 4, 5, 6, 7, 8],
        'D': [10, 20, 30, 40, 50, 60, 70, 80]}
df = pd.DataFrame(data)

# 使用groupby执行数据过滤
filtered_data = df.groupby('A').get_group('foo')

# 执行逐个元素的减法
df['E'] = df['C'] - df['D']

# 打印结果
print("Filtered Data:")
print(filtered_data)
print("\nSubtraction Result:")
print(df)

Filtered Data:
     A    B  C   D
0  foo  one  1  10
2  foo  two  3  30
4  foo  two  5  50
6  foo  two  7  70
7  foo  one  8  80

Subtraction Result:
     A    B  C   D   E
0  foo  one  1  10  -9
1  bar  one  2  20 -18
2  foo  two  3  30 -27
3  bar  two  4  40 -36
4  foo  two  5  50 -45
5  bar  one  6  60 -54
6  foo  two  7  70 -63
7  foo  one  8  80 -72