Pandas-先前行值的累加和

import pandas as pd

# 创建一个包含数值的DataFrame
df = pd.DataFrame({'A': [1, 2, 3, 4, 5]})

# 使用shift()函数将列向下移动一行
df['shifted_A'] = df['A'].shift(1)

# 使用cumsum()函数计算累加和
df['cumulative_sum'] = df['shifted_A'].cumsum()

print(df)

   A  shifted_A  cumulative_sum
0  1        NaN             NaN
1  2        1.0             1.0
2  3        2.0             3.0
3  4        3.0             6.0
4  5        4.0            10.0