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TextClassificationDataset

The TextClassificationDataset class represents a text classification dataset.

Each dataset element is a Python dictionary with the keys:

  • "document": the document as a string
  • "label": the document label as a string

The dataset is split into:

  • train
  • dev
  • test

Each split is a torch.utils.data.Dataset providing:

  • __len__: number of documents in the dataset
  • __getitem__: return the requested sentence as an Element dictionary with keys "document" and "label"
  • label_vocab, which is a npfl138.Vocabulary instance with the label mapping

npfl138.datasets.text_classification_dataset.TextClassificationDataset

Source code in npfl138/datasets/text_classification_dataset.py 
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class TextClassificationDataset:
    Element = TypedDict("Element", {"document": str, "label": str})
    """The type of a single dataset element, i.e., a single document and its label."""
    Elements = TypedDict("Elements", {"documents": list[str], "labels": list[str]})
    """The type of the whole dataset, i.e., a corpus of documents."""

    URL: str = "https://ufal.mff.cuni.cz/~straka/courses/npfl138/2526/datasets"

    class Dataset(torch.utils.data.Dataset):
        def __init__(self, data_file: BinaryIO, train: Self | None = None) -> None:
            # Load the data
            self._data: "TextClassificationDataset.Elements" = {
                "documents": [],
                "labels": [],
            }
            for line in data_file:
                line = line.decode("utf-8").rstrip("\r\n")
                label, document = line.split("\t", maxsplit=1)

                self._data["documents"].append(document)
                self._data["labels"].append(label)

            # Create or copy the label mapping
            if train:
                self._label_vocab = train._label_vocab
            else:
                self._label_vocab = Vocabulary(sorted(set(self._data["labels"])))

        @property
        def data(self) -> "TextClassificationDataset.Elements":
            """Return the whole dataset as a `TextClassificationDataset.Elements` object."""
            return self._data

        @property
        def label_vocab(self) -> Vocabulary:
            """The label vocabulary of the dataset."""
            return self._label_vocab

        def __len__(self) -> int:
            """Return the number of documents in the dataset."""
            return len(self._data["labels"])

        def __getitem__(self, index: int) -> "TextClassificationDataset.Element":
            """Return the `index`-th element of the dataset as a dictionary."""
            return {key.removesuffix("s"): value[index] for key, value in self._data.items()}

    def __init__(self, dataset: str) -> None:
        """Load the `dataset` dataset, downloading it if necessary.
        Parameters:
          dataset: The name of the dataset, for example `czech_facebook`.
        """
        path = download_url_to_file(self.URL, f"{dataset}.zip")

        with zipfile.ZipFile(path, "r") as zip_file:
            for split in ["train", "dev", "test"]:
                with zip_file.open(f"{dataset}_{split}.txt", "r") as dataset_file:
                    setattr(self, split, self.Dataset(dataset_file, train=getattr(self, "train", None)))

    train: Dataset
    """The training dataset."""
    dev: Dataset
    """The development dataset."""
    test: Dataset
    """The test dataset."""

    # Evaluation infrastructure.
    @staticmethod
    def evaluate(gold_dataset: Dataset, predictions: Sequence[str]) -> float:
        """Evaluate the `predictions` against the gold dataset.

        Returns:
          accuracy: The accuracy of the prediction.
        """
        gold = gold_dataset.data["labels"]

        if len(predictions) != len(gold):
            raise RuntimeError("The predictions are of different size than gold data: {} vs {}".format(
                len(predictions), len(gold)))

        correct = sum(gold[i] == predictions[i] for i in range(len(gold)))
        return correct / len(gold)

    @staticmethod
    def evaluate_file(gold_dataset: Dataset, predictions_file: TextIO) -> float:
        """Evaluate the file with predictions against the gold dataset.

        Returns:
          accuracy: The accuracy of the predictions.
        """
        predictions = [line.rstrip("\r\n") for line in predictions_file]
        return TextClassificationDataset.evaluate(gold_dataset, predictions)

Element class-attribute instance-attribute 

Element = TypedDict('Element', {'document': str, 'label': str})

The type of a single dataset element, i.e., a single document and its label.

Elements class-attribute instance-attribute 

Elements = TypedDict('Elements', {'documents': list[str], 'labels': list[str]})

The type of the whole dataset, i.e., a corpus of documents.

Dataset

Bases: Dataset

Source code in npfl138/datasets/text_classification_dataset.py 
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class Dataset(torch.utils.data.Dataset):
    def __init__(self, data_file: BinaryIO, train: Self | None = None) -> None:
        # Load the data
        self._data: "TextClassificationDataset.Elements" = {
            "documents": [],
            "labels": [],
        }
        for line in data_file:
            line = line.decode("utf-8").rstrip("\r\n")
            label, document = line.split("\t", maxsplit=1)

            self._data["documents"].append(document)
            self._data["labels"].append(label)

        # Create or copy the label mapping
        if train:
            self._label_vocab = train._label_vocab
        else:
            self._label_vocab = Vocabulary(sorted(set(self._data["labels"])))

    @property
    def data(self) -> "TextClassificationDataset.Elements":
        """Return the whole dataset as a `TextClassificationDataset.Elements` object."""
        return self._data

    @property
    def label_vocab(self) -> Vocabulary:
        """The label vocabulary of the dataset."""
        return self._label_vocab

    def __len__(self) -> int:
        """Return the number of documents in the dataset."""
        return len(self._data["labels"])

    def __getitem__(self, index: int) -> "TextClassificationDataset.Element":
        """Return the `index`-th element of the dataset as a dictionary."""
        return {key.removesuffix("s"): value[index] for key, value in self._data.items()}

data property 

data: Elements

Return the whole dataset as a TextClassificationDataset.Elements object.

label_vocab property 

label_vocab: Vocabulary

The label vocabulary of the dataset.

__len__ 

__len__() -> int

Return the number of documents in the dataset.

Source code in npfl138/datasets/text_classification_dataset.py 
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def __len__(self) -> int:
    """Return the number of documents in the dataset."""
    return len(self._data["labels"])

__getitem__ 

__getitem__(index: int) -> Element

Return the index-th element of the dataset as a dictionary.

Source code in npfl138/datasets/text_classification_dataset.py 
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def __getitem__(self, index: int) -> "TextClassificationDataset.Element":
    """Return the `index`-th element of the dataset as a dictionary."""
    return {key.removesuffix("s"): value[index] for key, value in self._data.items()}

__init__ 

__init__(dataset: str) -> None

Load the dataset dataset, downloading it if necessary. Parameters: dataset: The name of the dataset, for example czech_facebook.

Source code in npfl138/datasets/text_classification_dataset.py 
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def __init__(self, dataset: str) -> None:
    """Load the `dataset` dataset, downloading it if necessary.
    Parameters:
      dataset: The name of the dataset, for example `czech_facebook`.
    """
    path = download_url_to_file(self.URL, f"{dataset}.zip")

    with zipfile.ZipFile(path, "r") as zip_file:
        for split in ["train", "dev", "test"]:
            with zip_file.open(f"{dataset}_{split}.txt", "r") as dataset_file:
                setattr(self, split, self.Dataset(dataset_file, train=getattr(self, "train", None)))

train instance-attribute 

train: Dataset

The training dataset.

dev instance-attribute 

dev: Dataset

The development dataset.

test instance-attribute 

test: Dataset

The test dataset.

evaluate staticmethod 

evaluate(gold_dataset: Dataset, predictions: Sequence[str]) -> float

Evaluate the predictions against the gold dataset.

Returns:

  • accuracy ( float ) –

    The accuracy of the prediction.

Source code in npfl138/datasets/text_classification_dataset.py 
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@staticmethod
def evaluate(gold_dataset: Dataset, predictions: Sequence[str]) -> float:
    """Evaluate the `predictions` against the gold dataset.

    Returns:
      accuracy: The accuracy of the prediction.
    """
    gold = gold_dataset.data["labels"]

    if len(predictions) != len(gold):
        raise RuntimeError("The predictions are of different size than gold data: {} vs {}".format(
            len(predictions), len(gold)))

    correct = sum(gold[i] == predictions[i] for i in range(len(gold)))
    return correct / len(gold)

evaluate_file staticmethod 

evaluate_file(gold_dataset: Dataset, predictions_file: TextIO) -> float

Evaluate the file with predictions against the gold dataset.

Returns:

  • accuracy ( float ) –

    The accuracy of the predictions.

Source code in npfl138/datasets/text_classification_dataset.py 
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@staticmethod
def evaluate_file(gold_dataset: Dataset, predictions_file: TextIO) -> float:
    """Evaluate the file with predictions against the gold dataset.

    Returns:
      accuracy: The accuracy of the predictions.
    """
    predictions = [line.rstrip("\r\n") for line in predictions_file]
    return TextClassificationDataset.evaluate(gold_dataset, predictions)