怎么引用features（def __getitem__(self, idx): sample = self.data.iloc[idx] features = sample[:-1].values）

根据APA格式，可以在文中使用以下方式引用features：

According to the code, the features are extracted using the following line: "features = sample[:-1].values" (Author, Year, line number).

例如：

According to the code, the features are extracted using the following line: "features = sample[:-1].values" (Smith, 2021, line 25).