Python Pandas条件求和并减去上一行

import pandas as pd

# 创建示例数据
data = {
    'date': ['2023-01-01', '2023-01-02', '2023-01-03', '2023-01-04'],
    'profit': [100, 150, 200, 180]
}
df = pd.DataFrame(data)

# 将日期列转换为 datetime 类型
df['date'] = pd.to_datetime(df['date'])

# 计算条件求和并减去上一行的值
df['adjusted_profit'] = df['profit'] - df['profit'].shift(1)

print(df)

        date  profit  adjusted_profit
0 2023-01-01     100             NaN
1 2023-01-02     150             50.0
2 2023-01-03     200             50.0
3 2023-01-04     180            -20.0

df['adjusted_profit'] = df['profit'] - df['profit'].shift(1)
df['adjusted_profit'].fillna(0, inplace=True)

print(df)

        date  profit  adjusted_profit
0 2023-01-01     100               0
1 2023-01-02     150               50
2 2023-01-03     200               50
3 2023-01-04     180              -20