如何根据列条目的特定条件修改pandas列数据？

import pandas as pd

# 创建一个示例DataFrame
data = {'Name': ['Alice', 'Bob', 'Charlie', 'David'],
        'Age': [25, 30, 35, 40],
        'Gender': ['Female', 'Male', 'Male', 'Male']}
df = pd.DataFrame(data)

# 根据条件修改列数据
df.loc[df['Age'] > 30, 'Gender'] = 'Unknown'

# 打印修改后的DataFrame
print(df)

      Name  Age   Gender
0    Alice   25   Female
1      Bob   30     Male
2  Charlie   35  Unknown
3    David   40  Unknown