# Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
# Copyright 2018 The Google AI Language Team Authors and The HuggingFace Inc. team.
#
# 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.
import os
from paddlenlp.transformers import (
BasicTokenizer,
PretrainedTokenizer,
WordpieceTokenizer,
)
__all__ = [
"SqueezeBertTokenizer",
]
[docs]
class SqueezeBertTokenizer(PretrainedTokenizer):
"""
Constructs a SqueezeBert tokenizer. It uses a basic tokenizer to do punctuation
splitting, lower casing and so on, and follows a WordPiece tokenizer to
tokenize as subwords.
Args:
vocab_file (str): file path of the vocabulary
do_lower_case (bool): Whether the text strips accents and convert to
lower case. Default: `True`.
Default: True.
unk_token (str): The special token for unkown words. Default: "[UNK]".
sep_token (str): The special token for separator token . Default: "[SEP]".
pad_token (str): The special token for padding. Default: "[PAD]".
cls_token (str): The special token for cls. Default: "[CLS]".
mask_token (str): The special token for mask. Default: "[MASK]".
Examples:
.. code-block:: python
from paddlenlp.transformers import SqueezeBertTokenizer
tokenizer = SqueezeBertTokenizer.from_pretrained('squeezebert-uncased')
# the following line get: ['he', 'was', 'a', 'puppet', '##eer']
tokens = tokenizer('He was a puppeteer')
# the following line get: 'he was a puppeteer'
tokenizer.convert_tokens_to_string(tokens)
"""
resource_files_names = {"vocab_file": "vocab.txt"} # for save_pretrained
pretrained_resource_files_map = {
"vocab_file": {
"squeezebert-uncased": "http://bj.bcebos.com/paddlenlp/models/transformers/squeezebert/squeezebert-uncased/vocab.txt",
"squeezebert-mnli": "http://bj.bcebos.com/paddlenlp/models/transformers/squeezebert/squeezebert-mnli/vocab.txt",
"squeezebert-mnli-headless": "http://bj.bcebos.com/paddlenlp/models/transformers/squeezebert/squeezebert-mnli-headless/vocab.txt",
}
}
pretrained_init_configuration = {
"squeezebert-uncased": {"do_lower_case": True},
"squeezebert-mnli": {"do_lower_case": True},
"squeezebert-mnli-headless": {"do_lower_case": True},
}
def __init__(
self,
vocab_file,
do_lower_case=True,
unk_token="[UNK]",
sep_token="[SEP]",
pad_token="[PAD]",
cls_token="[CLS]",
mask_token="[MASK]",
**kwargs
):
if not os.path.isfile(vocab_file):
raise ValueError(
"Can't find a vocabulary file at path '{}'. To load the "
"vocabulary from a pretrained model please use "
"`tokenizer = SqueezeBertTokenizer.from_pretrained(PRETRAINED_MODEL_NAME)`".format(vocab_file)
)
self.vocab = self.load_vocabulary(vocab_file, unk_token=unk_token)
self.basic_tokenizer = BasicTokenizer(do_lower_case=do_lower_case)
self.wordpiece_tokenizer = WordpieceTokenizer(vocab=self.vocab, unk_token=unk_token)
@property
def vocab_size(self):
"""
return the size of vocabulary.
Returns:
int: the size of vocabulary.
"""
return len(self.vocab)
[docs]
def get_vocab(self):
return dict(self.vocab.token_to_idx, **self.added_tokens_encoder)
def _tokenize(self, text):
"""
End-to-end tokenization for SqueezeBert models.
Args:
text (str): The text to be tokenized.
Returns:
list: A list of string representing converted tokens.
"""
split_tokens = []
for token in self.basic_tokenizer.tokenize(text):
for sub_token in self.wordpiece_tokenizer.tokenize(token):
split_tokens.append(sub_token)
return split_tokens
[docs]
def convert_tokens_to_string(self, tokens):
"""
Converts a sequence of tokens (list of string) in a single string. Since
the usage of WordPiece introducing `##` to concat subwords, also remove
`##` when converting.
Args:
tokens (list): A list of string representing tokens to be converted.
Returns:
str: Converted string from tokens.
"""
out_string = " ".join(tokens).replace(" ##", "").strip()
return out_string
[docs]
def num_special_tokens_to_add(self, pair=False):
"""
Returns the number of added tokens when encoding a sequence with special tokens.
Note:
This encodes inputs and checks the number of added tokens, and is therefore not efficient. Do not put this
inside your training loop.
Args:
pair: Returns the number of added tokens in the case of a sequence pair if set to True, returns the
number of added tokens in the case of a single sequence if set to False.
Returns:
Number of tokens added to sequences
"""
token_ids_0 = []
token_ids_1 = []
return len(self.build_inputs_with_special_tokens(token_ids_0, token_ids_1 if pair else None))
[docs]
def build_offset_mapping_with_special_tokens(self, offset_mapping_0, offset_mapping_1=None):
"""
Build offset map from a pair of offset map by concatenating and adding offsets of special tokens.
A SqueezeBert offset_mapping has the following format:
::
- single sequence: ``(0,0) X (0,0)``
- pair of sequences: `(0,0) A (0,0) B (0,0)``
Args:
offset_mapping_ids_0 (:obj:`List[tuple]`):
List of char offsets to which the special tokens will be added.
offset_mapping_ids_1 (:obj:`List[tuple]`, `optional`):
Optional second list of char offsets for offset mapping pairs.
Returns:
:obj:`List[tuple]`: List of char offsets with the appropriate offsets of special tokens.
"""
if offset_mapping_1 is None:
return [(0, 0)] + offset_mapping_0 + [(0, 0)]
return [(0, 0)] + offset_mapping_0 + [(0, 0)] + offset_mapping_1 + [(0, 0)]
[docs]
def create_token_type_ids_from_sequences(self, token_ids_0, token_ids_1=None):
"""
Create a mask from the two sequences passed to be used in a sequence-pair classification task.
A SqueezeBert 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 :obj:`token_ids_1` is :obj:`None`, this method only returns the first portion of the mask (0s).
Args:
token_ids_0 (:obj:`List[int]`):
List of IDs.
token_ids_1 (:obj:`List[int]`, `optional`):
Optional second list of IDs for sequence pairs.
Returns:
:obj:`List[int]`: List of token_type_id according to the given sequence(s).
"""
_sep = [self.sep_token_id]
_cls = [self.cls_token_id]
if token_ids_1 is None:
return len(_cls + token_ids_0 + _sep) * [0]
return len(_cls + token_ids_0 + _sep) * [0] + len(token_ids_1 + _sep) * [1]
[docs]
def get_special_tokens_mask(self, token_ids_0, token_ids_1=None, already_has_special_tokens=False):
"""
Retrieves sequence ids from a token list that has no special tokens added. This method is called when adding
special tokens using the tokenizer ``encode`` methods.
Args:
token_ids_0 (List[int]): List of ids of the first sequence.
token_ids_1 (List[int], optional): List of ids of the second sequence.
already_has_special_tokens (bool, optional): Whether or not the token list is already
formatted with special tokens for the model. Defaults to None.
Returns:
results (List[int]): The list of integers in the range [0, 1]: 1 for a special token, 0 for a sequence token.
"""
if already_has_special_tokens:
if token_ids_1 is not None:
raise ValueError(
"You should not supply a second sequence if the provided sequence of "
"ids is already formatted with special tokens for the model."
)
return list(map(lambda x: 1 if x in [self.sep_token_id, self.cls_token_id] else 0, token_ids_0))
if token_ids_1 is not None:
return [1] + ([0] * len(token_ids_0)) + [1] + ([0] * len(token_ids_1)) + [1]
return [1] + ([0] * len(token_ids_0)) + [1]
