pandas 按条件新增列

 import  pandas as pd

import numpy as np

df=pd.DataFrame({'amount':[100,200,300,400,500],'list':['','商品1','商品2','','商品3']})

df['x1'] = df.apply(lambda x: x.amount if x.list != "" else 0, axis=1)

df['x2']=np.where(df['list']=='',0,df['amount'])

df.loc[df['list']!='','x3']=df['amount']

df=df.fillna(0)