如何从Dataframe列的逗号分隔字符串中提取数据库名和表名到两列

import pandas as pd

# 创建Dataframe对象
df = pd.DataFrame({'column_name': ['database1.table1, database2.table2, database3.table3']})

# 定义函数来提取数据库名和表名
def extract_names(row):
    names = row.split(',')  # 使用逗号分隔字符串
    db_names = []
    table_names = []
    for name in names:
        name_parts = name.strip().split('.')  # 使用点号分隔数据库名和表名
        if len(name_parts) == 2:
            db_names.append(name_parts[0])
            table_names.append(name_parts[1])
        else:
            db_names.append('')
            table_names.append('')
    return pd.Series({'database_name': ','.join(db_names), 'table_name': ','.join(table_names)})

# 应用函数到Dataframe的列中
df[['database_name', 'table_name']] = df['column_name'].apply(lambda x: extract_names(x))

print(df)

                                     column_name  database_name        table_name
0  database1.table1, database2.table2, database3.table3  database1,database2,database3  table1,table2,table3