pandas.errors.IndexingError: Too many indexers

Question

得到错误消息太多索引器使用pandas。下列代码

import pandas as pd
userlist = ['Smith', 'Clark']
df = pd.read_csv("sample.csv")  
for i, df in df.iterrows():    
if (df['Last Name']) in userlist:
df.at[1,'Runner']='Yes'        
else:
pass

csv:
Last Name,Frist Name,email,Runner,Vistor
Doe,John,[e-mail],Yes,Yes
Smith,Shawn,[e-mail],No,Yes
Brown,Beth,[e-mail],Yes,No
Clark,Tom,[e-mail],No,Yes

我有一个大型数据集，其中包含需要更新单元格的名称列表，并将循环遍历列表以更改单元格。请帮助。由于

Answer 1

import pandas as pd
userlist = ['Smith', 'Clark']
df = pd.read_csv("sample.csv") 
df['Runner'][df['Last Name'].isin(userlist)]='Yes'