我创建了一个dataFrame，它是输出：
print(train_df)
author text
0 BernardHickey The Commmonwealth Bank of Australia (CBA) warn...
1 BernardHickey Rupert Murdoch predicted in a newspaper interv...
2 BernardHickey News Corp Ltd chairman and chief executive Rup...
3 BernardHickey Rupert Murdoch on Tuesday reported that News C...
4 BernardHickey Rupert Murdoch on Tuesday reported that News C...
然后我保存了数据框：
train_df.to_csv(data_path+'/train.csv')
当我再次阅读它时：
data = pd.read_csv(data_path+'/train.csv')
data.head(10)
Unnamed: 0 author text
0 0 BernardHickey The Commmonwealth Bank of Australia (CBA) warn...
1 1 BernardHickey Rupert Murdoch predicted in a newspaper interv...
2 2 BernardHickey News Corp Ltd chairman and chief executive Rup...
3 3 BernardHickey Rupert Murdoch on Tuesday reported that News C...
为什么那里有Unnamed列？我该如何避免呢？