Pandas:如果条件匹配，如何仅更新最多n行

selected_rows = df[df['条件列'] == '条件值']

selected_rows = selected_rows[:n]

df.loc[selected_rows.index, '更新列'] = '更新值'

import pandas as pd

# 创建一个示例DataFrame
data = {'条件列': ['条件值1', '条件值2', '条件值3', '条件值4', '条件值5'],
        '更新列': ['原始值1', '原始值2', '原始值3', '原始值4', '原始值5']}
df = pd.DataFrame(data)

# 条件匹配并选取最多3行进行更新
selected_rows = df[df['条件列'] == '条件值']
selected_rows = selected_rows[:3]
df.loc[selected_rows.index, '更新列'] = '更新值'

# 打印更新后的DataFrame
print(df)