按条件将行列表与一列相乘（DATA FRAME）

Question

我想将一个列的列表乘以一个列，所以我有列的列表 = cols，但我只想乘以那些行 name=="A" .with 列 "multi"

data={"col1":[2,3,4,5],
"col2":[4,2,4,6],
"col3":[7,6,9,11],
"col4":[14,11,22,8],
"name":["A","A","V","A"],
"multi":[1.4,2.5,1.6,2.2]}
df=pd.DataFrame.from_dict(data)
cols=list(df.columns)
for x in ["multi","name","col4"]:
    cols.remove(x)
df

像这样

df[cols]=df.loc[df["name"]=="A"]*df["multi"]

Answer 1

让我们做

m = ~df.columns.isin(["multi","name","col4"])
df.loc[df.name=='A', m] = (df.loc[df.name=='A', m].mul(df.multi, axis=0))
df
Out[94]: 
   col1  col2  col3  col4 name  multi
0   2.8   5.6   9.8    14    A    1.4
1   7.5   5.0  15.0    11    A    2.5
2   4.0   4.0   9.0    22    V    1.6
3  11.0  13.2  24.2     8    A    2.2

Answer 2

试试这个

df.loc[df.name=='A', cols] = df[df.name=='A'].apply(lambda r:r[cols]*r['multi'], axis=1)

按条件将行列表与一列相乘（DATA FRAME）

multiply list of row with one column by condition (DATA FRAME)

python

multiplication

conditional-statements

pandas