在列中搜索字符串，如果找到或未找到，则将另一个字符串添加到单独的列中

import pandas as pd

# 创建一个包含字符串的列A和一个空列D
data = {'A': ['abc', 'def', 'ghi', 'jkl']}
df = pd.DataFrame(data)
df['D'] = ''

# 定义要搜索的字符串B和要添加的字符串C和D
search_string = 'c'
string_c = 'Found'
string_d = 'Not Found'

# 遍历列A中的每个单元格
for index, row in df.iterrows():
    if search_string in row['A']:
        df.at[index, 'D'] = string_c
    else:
        df.at[index, 'D'] = string_d

# 打印结果
print(df)

     A          D
0  abc      Found
1  def  Not Found
2  ghi  Not Found
3  jkl  Not Found