将dataframe中的值替换为其他行的值，替换为"target row“

import pandas as pd

# 创建一个示例dataframe
data = {'A': [1, 2, 3, None, 5],
        'B': [6, None, 8, 9, 10],
        'C': [11, 12, None, 14, 15]}
df = pd.DataFrame(data)

# 要替换的值所在的行和列
row_index = 3
column_index = 'B'

# 获取目标行的值
target_row = df.iloc[row_index, :]

# 将目标行的值替换为"target row"
df.at[row_index, column_index] = "target row"

# 将其他行的值替换为"target row"
df = df.fillna("target row")

print(df)

           A           B           C
0          1           6          11
1          2  target row          12
2          3           8  target row
3  target row  target row  target row
4          5          10          15