如果我一次做一列cumsum，我可以讓它作業。然而，一起做會輸出 NaN。
df = pd.DataFrame({"category": [1,2,2], "value1": [10,11,12], "value2": [20,21,22]})
m = df["category"] == 2
df.loc[m, ["cum_value1", "cum_value2"]] = df.loc[m, ["value1", "value2"]].cumsum()
uj5u.com熱心網友回復：
您可以只分配新列
df[["cum_value1", "cum_value2"]] = df.loc[m, ["value1", "value2"]].cumsum()
df
Out[520]:
category value1 value2 cum_value1 cum_value2
0 1 10 20 NaN NaN
1 2 11 21 11.0 21.0
2 2 12 22 23.0 43.0
轉載請註明出處，本文鏈接：https://www.uj5u.com/qianduan/472475.html
標籤：熊猫