将值添加到现有行-DataFrame

import pandas as pd

# 创建一个示例DataFrame
data = {'Name': ['John', 'Emma', 'Mike'],
        'Age': [25, 28, 30],
        'City': ['New York', 'London', 'Paris']}
df = pd.DataFrame(data)

# 打印原始DataFrame
print("原始DataFrame:")
print(df)

# 使用loc方法将值添加到现有行
df.loc[1, 'Age'] = 29

# 打印更新后的DataFrame
print("更新后的DataFrame:")
print(df)

原始DataFrame:
   Name  Age      City
0  John   25  New York
1  Emma   28    London
2  Mike   30     Paris
更新后的DataFrame:
   Name  Age      City
0  John   25  New York
1  Emma   29    London
2  Mike   30     Paris