code: # coding=utf-8
  # Copyright 2018 The Google AI Language Team Authors and The HuggingFace Inc. team.
  # Copyright (c) 2018, NVIDIA CORPORATION.  All rights reserved.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  """ Multiple choice fine-tuning: utilities to work with multiple choice tasks of reading comprehension """
  
  
  import csv
  import glob
  import json
  import logging
  import os
  from dataclasses import dataclass
  from enum import Enum
  from typing import List, Optional
  
  import tqdm
  
  from filelock import FileLock
  from transformers import PreTrainedTokenizer, is_tf_available, is_torch_available
  
  
  logger = logging.getLogger(__name__)
  
  
  @dataclass(frozen=True)
  class InputExample:
      """
      A single training/test example for multiple choice
  
      Args:
          example_id: Unique id for the example.
          question: string. The untokenized text of the second sequence (question).
          contexts: list of str. The untokenized text of the first sequence (context of corresponding question).
          endings: list of str. multiple choice's options. Its length must be equal to contexts' length.
          label: (Optional) string. The label of the example. This should be
          specified for train and dev examples, but not for test examples.
      """
  
      example_id: str
      question: str
      contexts: List[str]
      endings: List[str]
      label: Optional[str]
  
  
  @dataclass(frozen=True)
  class InputFeatures:
      """
      A single set of features of data.
      Property names are the same names as the corresponding inputs to a model.
      """
  
      example_id: str
      input_ids: List[List[int]]
      attention_mask: Optional[List[List[int]]]
      token_type_ids: Optional[List[List[int]]]
      label: Optional[int]
  
  
  class Split(Enum):
      train = "train"
      dev = "dev"
      test = "test"
  
  
  if is_torch_available():
      import torch
      from torch.utils.data.dataset import Dataset
  
      class MultipleChoiceDataset(Dataset):
          """
          This will be superseded by a framework-agnostic approach
          soon.
          """
  
          features: List[InputFeatures]
  
          def __init__(
              self,
              data_dir: str,
              tokenizer: PreTrainedTokenizer,
              task: str,
              max_seq_length: Optional[int] = None,
              overwrite_cache=False,
              mode: Split = Split.train,
          ):
              processor = processors[task]()
  
              cached_features_file = os.path.join(
                  data_dir,
                  "cached_{}_{}_{}_{}".format(
                      mode.value,
                      tokenizer.__class__.__name__,
                      str(max_seq_length),
                      task,
                  ),
              )
  
              # Make sure only the first process in distributed training processes the dataset,
              # and the others will use the cache.
              lock_path = cached_features_file + ".lock"
              with FileLock(lock_path):
  
                  if os.path.exists(cached_features_file) and not overwrite_cache:
                      logger.info(f"Loading features from cached file {cached_features_file}")
                      self.features = torch.load(cached_features_file)
                  else:
                      logger.info(f"Creating features from dataset file at {data_dir}")
                      label_list = processor.get_labels()
                      if mode == Split.dev:
                          examples = processor.get_dev_examples(data_dir)
                      elif mode == Split.test:
                          examples = processor.get_test_examples(data_dir)
                      else:
                          examples = processor.get_train_examples(data_dir)
                      logger.info("Training examples: %s", len(examples))
                      self.features = convert_examples_to_features(
                          examples,
                          label_list,
                          max_seq_length,
                          tokenizer,
                      )
                      logger.info("Saving features into cached file %s", cached_features_file)
                      torch.save(self.features, cached_features_file)
  
          def __len__(self):
              return len(self.features)
  
          def __getitem__(self, i) -> InputFeatures:
              return self.features[i]
  
  
  if is_tf_available():
      import tensorflow as tf
  
      class TFMultipleChoiceDataset:
          """
          This will be superseded by a framework-agnostic approach
          soon.
          """
  
          features: List[InputFeatures]
  
          def __init__(
              self,
              data_dir: str,
              tokenizer: PreTrainedTokenizer,
              task: str,
              max_seq_length: Optional[int] = 128,
              overwrite_cache=False,
              mode: Split = Split.train,
          ):
              processor = processors[task]()
  
              logger.info(f"Creating features from dataset file at {data_dir}")
              label_list = processor.get_labels()
              if mode == Split.dev:
                  examples = processor.get_dev_examples(data_dir)
              elif mode == Split.test:
                  examples = processor.get_test_examples(data_dir)
              else:
                  examples = processor.get_train_examples(data_dir)
              logger.info("Training examples: %s", len(examples))
  
              self.features = convert_examples_to_features(
                  examples,
                  label_list,
                  max_seq_length,
                  tokenizer,
              )
  
              def gen():
                  for (ex_index, ex) in tqdm.tqdm(enumerate(self.features), desc="convert examples to features"):
                      if ex_index % 10000 == 0:
                          logger.info("Writing example %d of %d" % (ex_index, len(examples)))
  
                      yield (
                          {
                              "example_id": 0,
                              "input_ids": ex.input_ids,
                              "attention_mask": ex.attention_mask,
                              "token_type_ids": ex.token_type_ids,
                          },
                          ex.label,
                      )
  
              self.dataset = tf.data.Dataset.from_generator(
                  gen,
                  (
                      {
                          "example_id": tf.int32,
                          "input_ids": tf.int32,
                          "attention_mask": tf.int32,
                          "token_type_ids": tf.int32,
                      },
                      tf.int64,
                  ),
                  (
                      {
                          "example_id": tf.TensorShape([]),
                          "input_ids": tf.TensorShape([None, None]),
                          "attention_mask": tf.TensorShape([None, None]),
                          "token_type_ids": tf.TensorShape([None, None]),
                      },
                      tf.TensorShape([]),
                  ),
              )
  
          def get_dataset(self):
              self.dataset = self.dataset.apply(tf.data.experimental.assert_cardinality(len(self.features)))
  
              return self.dataset
  
          def __len__(self):
              return len(self.features)
  
          def __getitem__(self, i) -> InputFeatures:
              return self.features[i]
  
  
  class DataProcessor:
      """Base class for data converters for multiple choice data sets."""
  
      def get_train_examples(self, data_dir):
          """Gets a collection of `InputExample`s for the train set."""
          raise NotImplementedError()
  
      def get_dev_examples(self, data_dir):
          """Gets a collection of `InputExample`s for the dev set."""
          raise NotImplementedError()
  
      def get_test_examples(self, data_dir):
          """Gets a collection of `InputExample`s for the test set."""
          raise NotImplementedError()
  
      def get_labels(self):
          """Gets the list of labels for this data set."""
          raise NotImplementedError()
  
  
  class RaceProcessor(DataProcessor):
      """Processor for the RACE data set."""
  
      def get_train_examples(self, data_dir):
          """See base class."""
          logger.info("LOOKING AT {} train".format(data_dir))
          high = os.path.join(data_dir, "train/high")
          middle = os.path.join(data_dir, "train/middle")
          high = self._read_txt(high)
          middle = self._read_txt(middle)
          return self._create_examples(high + middle, "train")
  
      def get_dev_examples(self, data_dir):
          """See base class."""
          logger.info("LOOKING AT {} dev".format(data_dir))
          high = os.path.join(data_dir, "dev/high")
          middle = os.path.join(data_dir, "dev/middle")
          high = self._read_txt(high)
          middle = self._read_txt(middle)
          return self._create_examples(high + middle, "dev")
  
      def get_test_examples(self, data_dir):
          """See base class."""
          logger.info("LOOKING AT {} test".format(data_dir))
          high = os.path.join(data_dir, "test/high")
          middle = os.path.join(data_dir, "test/middle")
          high = self._read_txt(high)
          middle = self._read_txt(middle)
          return self._create_examples(high + middle, "test")
  
      def get_labels(self):
          """See base class."""
          return ["0", "1", "2", "3"]
  
      def _read_txt(self, input_dir):
          lines = []
          files = glob.glob(input_dir + "/*txt")
          for file in tqdm.tqdm(files, desc="read files"):
              with open(file, "r", encoding="utf-8") as fin:
                  data_raw = json.load(fin)
                  data_raw["race_id"] = file
                  lines.append(data_raw)
          return lines
  
      def _create_examples(self, lines, set_type):
          """Creates examples for the training and dev sets."""
          examples = []
          for (_, data_raw) in enumerate(lines):
              race_id = "%s-%s" % (set_type, data_raw["race_id"])
              article = data_raw["article"]
              for i in range(len(data_raw["answers"])):
                  truth = str(ord(data_raw["answers"][i]) - ord("A"))
                  question = data_raw["questions"][i]
                  options = data_raw["options"][i]
  
                  examples.append(
                      InputExample(
                          example_id=race_id,
                          question=question,
                          contexts=[article, article, article, article],  # this is not efficient but convenient
                          endings=[options[0], options[1], options[2], options[3]],
                          label=truth,
                      )
                  )
          return examples
  
  
  class SynonymProcessor(DataProcessor):
      """Processor for the Synonym data set."""
  
      def get_train_examples(self, data_dir):
          """See base class."""
          logger.info("LOOKING AT {} train".format(data_dir))
          return self._create_examples(self._read_csv(os.path.join(data_dir, "mctrain.csv")), "train")
  
      def get_dev_examples(self, data_dir):
          """See base class."""
          logger.info("LOOKING AT {} dev".format(data_dir))
          return self._create_examples(self._read_csv(os.path.join(data_dir, "mchp.csv")), "dev")
  
      def get_test_examples(self, data_dir):
          """See base class."""
          logger.info("LOOKING AT {} dev".format(data_dir))
  
          return self._create_examples(self._read_csv(os.path.join(data_dir, "mctest.csv")), "test")
  
      def get_labels(self):
          """See base class."""
          return ["0", "1", "2", "3", "4"]
  
      def _read_csv(self, input_file):
          with open(input_file, "r", encoding="utf-8") as f:
              return list(csv.reader(f))
  
      def _create_examples(self, lines: List[List[str]], type: str):
          """Creates examples for the training and dev sets."""
  
          examples = [
              InputExample(
                  example_id=line[0],
                  question="",  # in the swag dataset, the
                  # common beginning of each
                  # choice is stored in "sent2".
                  contexts=[line[1], line[1], line[1], line[1], line[1]],
                  endings=[line[2], line[3], line[4], line[5], line[6]],
                  label=line[7],
              )
              for line in lines  # we skip the line with the column names
          ]
  
          return examples
  
  
  class SwagProcessor(DataProcessor):
      """Processor for the SWAG data set."""
  
      def get_train_examples(self, data_dir):
          """See base class."""
          logger.info("LOOKING AT {} train".format(data_dir))
          return self._create_examples(self._read_csv(os.path.join(data_dir, "train.csv")), "train")
  
      def get_dev_examples(self, data_dir):
          """See base class."""
          logger.info("LOOKING AT {} dev".format(data_dir))
          return self._create_examples(self._read_csv(os.path.join(data_dir, "val.csv")), "dev")
  
      def get_test_examples(self, data_dir):
          """See base class."""
          logger.info("LOOKING AT {} dev".format(data_dir))
          raise ValueError(
              "For swag testing, the input file does not contain a label column. It can not be tested in current code"
              "setting!"
          )
          return self._create_examples(self._read_csv(os.path.join(data_dir, "test.csv")), "test")
  
      def get_labels(self):
          """See base class."""
          return ["0", "1", "2", "3"]
  
      def _read_csv(self, input_file):
          with open(input_file, "r", encoding="utf-8") as f:
              return list(csv.reader(f))
  
      def _create_examples(self, lines: List[List[str]], type: str):
          """Creates examples for the training and dev sets."""
          if type == "train" and lines[0][-1] != "label":
              raise ValueError("For training, the input file must contain a label column.")
  
          examples = [
              InputExample(
                  example_id=line[2],
                  question=line[5],  # in the swag dataset, the
                  # common beginning of each
                  # choice is stored in "sent2".
                  contexts=[line[4], line[4], line[4], line[4]],
                  endings=[line[7], line[8], line[9], line[10]],
                  label=line[11],
              )
              for line in lines[1:]  # we skip the line with the column names
          ]
  
          return examples
  
  
  class ArcProcessor(DataProcessor):
      """Processor for the ARC data set (request from allennlp)."""
  
      def get_train_examples(self, data_dir):
          """See base class."""
          logger.info("LOOKING AT {} train".format(data_dir))
          return self._create_examples(self._read_json(os.path.join(data_dir, "train.jsonl")), "train")
  
      def get_dev_examples(self, data_dir):
          """See base class."""
          logger.info("LOOKING AT {} dev".format(data_dir))
          return self._create_examples(self._read_json(os.path.join(data_dir, "dev.jsonl")), "dev")
  
      def get_test_examples(self, data_dir):
          logger.info("LOOKING AT {} test".format(data_dir))
          return self._create_examples(self._read_json(os.path.join(data_dir, "test.jsonl")), "test")
  
      def get_labels(self):
          """See base class."""
          return ["0", "1", "2", "3"]
  
      def _read_json(self, input_file):
          with open(input_file, "r", encoding="utf-8") as fin:
              lines = fin.readlines()
              return lines
  
      def _create_examples(self, lines, type):
          """Creates examples for the training and dev sets."""
  
          # There are two types of labels. They should be normalized
          def normalize(truth):
              if truth in "ABCD":
                  return ord(truth) - ord("A")
              elif truth in "1234":
                  return int(truth) - 1
              else:
                  logger.info("truth ERROR! %s", str(truth))
                  return None
  
          examples = []
          three_choice = 0
          four_choice = 0
          five_choice = 0
          other_choices = 0
          # we deleted example which has more than or less than four choices
          for line in tqdm.tqdm(lines, desc="read arc data"):
              data_raw = json.loads(line.strip("\n"))
              if len(data_raw["question"]["choices"]) == 3:
                  three_choice += 1
                  continue
              elif len(data_raw["question"]["choices"]) == 5:
                  five_choice += 1
                  continue
              elif len(data_raw["question"]["choices"]) != 4:
                  other_choices += 1
                  continue
              four_choice += 1
              truth = str(normalize(data_raw["answerKey"]))
              assert truth != "None"
              question_choices = data_raw["question"]
              question = question_choices["stem"]
              id = data_raw["id"]
              options = question_choices["choices"]
              if len(options) == 4:
                  examples.append(
                      InputExample(
                          example_id=id,
                          question=question,
                          contexts=[
                              options[0]["para"].replace("_", ""),
                              options[1]["para"].replace("_", ""),
                              options[2]["para"].replace("_", ""),
                              options[3]["para"].replace("_", ""),
                          ],
                          endings=[options[0]["text"], options[1]["text"], options[2]["text"], options[3]["text"]],
                          label=truth,
                      )
                  )
  
          if type == "train":
              assert len(examples) > 1
              assert examples[0].label is not None
          logger.info("len examples: %s}", str(len(examples)))
          logger.info("Three choices: %s", str(three_choice))
          logger.info("Five choices: %s", str(five_choice))
          logger.info("Other choices: %s", str(other_choices))
          logger.info("four choices: %s", str(four_choice))
  
          return examples
  
  
  def convert_examples_to_features(
      examples: List[InputExample],
      label_list: List[str],
      max_length: int,
      tokenizer: PreTrainedTokenizer,
  ) -> List[InputFeatures]:
      """
      Loads a data file into a list of `InputFeatures`
      """
  
      label_map = {label: i for i, label in enumerate(label_list)}
  
      features = []
      for (ex_index, example) in tqdm.tqdm(enumerate(examples), desc="convert examples to features"):
          if ex_index % 10000 == 0:
              logger.info("Writing example %d of %d" % (ex_index, len(examples)))
          choices_inputs = []
          for ending_idx, (context, ending) in enumerate(zip(example.contexts, example.endings)):
              text_a = context
              if example.question.find("_") != -1:
                  # this is for cloze question
                  text_b = example.question.replace("_", ending)
              else:
                  text_b = example.question + " " + ending
  
              inputs = tokenizer(
                  text_a,
                  text_b,
                  add_special_tokens=True,
                  max_length=max_length,
                  padding="max_length",
                  truncation=True,
                  return_overflowing_tokens=True,
              )
              if "num_truncated_tokens" in inputs and inputs["num_truncated_tokens"] > 0:
                  logger.info(
                      "Attention! you are cropping tokens (swag task is ok). "
                      "If you are training ARC and RACE and you are poping question + options,"
                      "you need to try to use a bigger max seq length!"
                  )
  
              choices_inputs.append(inputs)
  
          label = label_map[example.label]
  
          input_ids = [x["input_ids"] for x in choices_inputs]
          attention_mask = (
              [x["attention_mask"] for x in choices_inputs] if "attention_mask" in choices_inputs[0] else None
          )
          token_type_ids = (
              [x["token_type_ids"] for x in choices_inputs] if "token_type_ids" in choices_inputs[0] else None
          )
  
          features.append(
              InputFeatures(
                  example_id=example.example_id,
                  input_ids=input_ids,
                  attention_mask=attention_mask,
                  token_type_ids=token_type_ids,
                  label=label,
              )
          )
  
      for f in features[:2]:
          logger.info("*** Example ***")
          logger.info("feature: %s" % f)
  
      return features
  
  
  processors = {"race": RaceProcessor, "swag": SwagProcessor, "arc": ArcProcessor, "syn": SynonymProcessor}
  MULTIPLE_CHOICE_TASKS_NUM_LABELS = {"race", 4, "swag", 4, "arc", 4, "syn", 5}
  