class int = None, tokenizer: = None, token_indexers: typing.Dict[str,] = None, lazy: bool = False) → None[source]


Reads a text file and converts it into a Dataset suitable for training a language model.

Note that there’s one issue that needs to be fixed before this is actually usable for language modeling - the way start and end tokens for sentences are handled is not correct; we need to add a sentence splitter before this will be done right.


tokens_per_instance : int, optional (default=``None``)

If this is None, we will have each training instance be a single sentence. If this is not None, we will instead take all sentences, including their start and stop tokens, line them up, and split the tokens into groups of this number, for more efficient training of the language model.

tokenizer : Tokenizer, optional (default=``WordTokenizer()``)

We use this Tokenizer for the text. See Tokenizer.

token_indexers : Dict[str, TokenIndexer], optional (default=``{“tokens”: SingleIdTokenIndexer()}``)

We use this to define the input representation for the text. See TokenIndexer. Note that the output representation will always be single token IDs - if you’ve specified a SingleIdTokenIndexer here, we use the first one you specify. Otherwise, we create one with default parameters.

classmethod from_params(params: allennlp.common.params.Params) →[source]
text_to_instance(sentence: str) →[source]

Does whatever tokenization or processing is necessary to go from textual input to an Instance. The primary intended use for this is with a Predictor, which gets text input as a JSON object and needs to process it to be input to a model.

The intent here is to share code between _read() and what happens at model serving time, or any other time you want to make a prediction from new data. We need to process the data in the same way it was done at training time. Allowing the DatasetReader to process new text lets us accomplish this, as we can just call DatasetReader.text_to_instance when serving predictions.

The input type here is rather vaguely specified, unfortunately. The Predictor will have to make some assumptions about the kind of DatasetReader that it’s using, in order to pass it the right information.