如何使用split()方法从现有的字符串列创建新的Dataframe列？

import pandas as pd

df = pd.DataFrame({'string_column': ['apple,banana,orange', 'cat,dog', 'sun,moon,star']})

df['new_column'] = df['string_column'].str.split(',')

df[['new_column1', 'new_column2', 'new_column3']] = df['string_column'].str.split(',', expand=True)

print(df)