Tokenization classes for LUKE.

class LukeTokenizer(vocab_file, entity_file, merges_file, do_lower_case=True, unk_token='<unk>', sep_token='</s>', pad_token='<pad>', cls_token='<s>', mask_token='<mask>', **kwargs)[source]#

Bases: RobertaBPETokenizer

Constructs a Luke tokenizer. It uses a basic tokenizer to do punctuation splitting, lower casing and so on, and follows a WordPiece tokenizer to tokenize as subwords.

This tokenizer inherits from PretrainedTokenizer which contains most of the main methods. For more information regarding those methods, please refer to this superclass.

  • vocab_file (str) – The vocabulary file path (ends with ‘.json’) required to instantiate a WordpieceTokenizer.

  • entity_file (str) – The entity vocabulary file path (ends with ‘.tsv’) required to instantiate a EntityTokenizer.

  • do_lower_case (bool) – Whether or not to lowercase the input when tokenizing. Defaults to`True`.

  • unk_token (str) – A special token representing the unknown (out-of-vocabulary) token. An unknown token is set to be unk_token inorder to be converted to an ID. Defaults to “[UNK]”.

  • sep_token (str) – A special token separating two different sentences in the same input. Defaults to “[SEP]”.

  • pad_token (str) – A special token used to make arrays of tokens the same size for batching purposes. Defaults to “[PAD]”.

  • cls_token (str) – A special token used for sequence classification. It is the last token of the sequence when built with special tokens. Defaults to “[CLS]”.

  • mask_token (str) – A special token representing a masked token. This is the token used in the masked language modeling task which the model tries to predict the original unmasked ones. Defaults to “[MASK]”.


from paddlenlp.transformers import LukeTokenizer
tokenizer = LukeTokenizer.from_pretrained('luke-large)

tokens = tokenizer('Beyoncé lives in Los Angeles', entity_spans=[(0, 7), (17, 28)])
#{'input_ids': [0, 40401, 261, 12695, 1074, 11, 1287, 1422, 2], 'entity_ids': [1657, 32]}
property sep_token_id#

Id of the separation token in the vocabulary, to separate context and query in an input sequence. Returns None if the token has not been set.



property cls_token_id#

Id of the classification token in the vocabulary, to extract a summary of an input sequence leveraging self-attention along the full depth of the model.

Returns None if the token has not been set.



property pad_token_id#

Id of the padding token in the vocabulary. Returns None if the token has not been set.



property unk_token_id#

Id of the unknown token in the vocabulary. Returns None if the token has not been set.




Get the entity vocab

tokenize(text, add_prefix_space=False)[source]#
Tokenize a string.
text (str):

The sentence to be tokenized.

add_prefix_space (boolean, default False):

Begin the sentence with at least one space to get invariance to word order in GPT-2 (and Luke) tokenizers.


Converts a sequence of tokens (string) in a single string.

add_special_tokens(token_list: List[int] | Dict)[source]#

Adding special tokens if you need.


token_list (List[int], Dict[List[int]]) – The special token list you provided. If you provide a Dict, the key of the Dict must be “additional_special_tokens” and the value must be token list.

convert_entity_to_id(entity: str)[source]#

Convert the entity to id

entity_encode(text, entities, max_mention_length, entity_spans, ent_sep=0, offset_a=1)[source]#

Convert the string entity to digital entity


Returns the map of tokens and the start and end index of their start and end character. Modified from bojone/bert4keras :param text: Input text. :type text: str :param split_tokens: the tokens which has been split which can accelerate the operation. :type split_tokens: Optional[List[str]]


The offset map of input text.

Return type:


create_token_type_ids_from_sequences(token_ids_0, token_ids_1=None)[source]#

Create a mask from the two sequences passed to be used in a sequence-pair classification task.

A Luke sequence pair mask has the following format:

0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1
| first sequence    | second sequence |

If token_ids_1 is None, this method only returns the first portion of the mask (0s).

  • token_ids_0 (List[int]) – A list of inputs_ids for the first sequence.

  • token_ids_1 (List[int], optional) – Optional second list of IDs for sequence pairs. Defaults to None.


List of token_type_id according to the given sequence(s).

Return type:



Returns the number of added tokens when encoding a sequence with special tokens.


pair (bool) – Whether the input is a sequence pair or a single sequence. Defaults to False and the input is a single sequence.


Number of tokens added to sequences.

Return type:


build_inputs_with_special_tokens(token_ids_0, token_ids_1=None)[source]#

Build model inputs from a sequence or a pair of sequence for sequence classification tasks by concatenating and adding special tokens.