text: 
  
  TITLE
  [trainer] a consistent way to limit the number of items
  
  COMMENTS
  30
  
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  # 🚀 Feature request
  
  We have:
  
  1.  `finetune_trainer.py` has
  ```
      n_train: Optional[int] = field(default=-1, metadata={"help": "# training examples. -1 means use all."})
      n_val: Optional[int] = field(default=-1, metadata={"help": "# validation examples. -1 means use all."})
      n_test: Optional[int] = field(default=-1, metadata={"help": "# test examples. -1 means use all."})
  ```
  2. some other `run_` scripts use `--n_obs`
  3. `--max_steps` in the main trainer - which works only on the train_dataset - no ability to limit items on eval_dataset
  
  Requests/Questions:
  
  1. How does one use `--max_steps` if one needs to use a different number of items for train and eval?
  2. Can we have a consistent way across examples to do this same thing?
  
  Thank you.
  
  @sgugger