在Pandas中，减去按ID分组的数据帧中每一年的连续行

import pandas as pd

# 创建一个示例数据帧
data = {
    'ID': ['A', 'A', 'A', 'B', 'B', 'B', 'B'],
    'Year': [2018, 2018, 2019, 2018, 2019, 2019, 2020],
    'Value': [10, 20, 30, 40, 50, 60, 70]
}
df = pd.DataFrame(data)

# 按照ID分组，并计算每一年的连续行之间的差异
df['Diff'] = df.groupby('ID')['Value'].diff()

# 打印结果
print(df)

  ID  Year  Value  Diff
0  A  2018     10   NaN
1  A  2018     20  10.0
2  A  2019     30  10.0
3  B  2018     40   NaN
4  B  2019     50  10.0
5  B  2019     60  10.0
6  B  2020     70  10.0