熊猫当前行上方/下方的总和列

Question

我试图在熊猫中实现这一目标：

df['X'] = df['C'].where(row is <= current row).sum()
df['Y'] = df['C'].where(row is >= current row).sum()

使 Pandas 对 C 列中高于或等于当前行的数据求和的正确语法是什么？

Answer 1

这是累积：

df['X'] = df['C'].cumsum()
df['Y'] = df['C'].sum() + df['C'] - df['X']
# or 
# df['Y'] = df.iloc[::-1].cumsum()