2415 lines
114 KiB
Python
2415 lines
114 KiB
Python
# coding=utf-8
|
|
# Copyright 2018 The Open AI 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.
|
|
"""Tokenization classes for OpenAI GPT."""
|
|
|
|
import copy
|
|
import functools
|
|
import itertools
|
|
import json
|
|
import logging
|
|
import operator
|
|
import os
|
|
import re
|
|
import collections
|
|
import unicodedata
|
|
|
|
from collections import UserDict, defaultdict
|
|
from contextlib import contextmanager
|
|
from typing import List, Optional, Sequence, Tuple, Union
|
|
|
|
from tokenizers import AddedToken, Encoding
|
|
from tokenizers.implementations import BaseTokenizer
|
|
|
|
from file_utils import cached_path, hf_bucket_url, is_remote_url, is_tf_available, is_torch_available
|
|
|
|
|
|
if is_tf_available():
|
|
import tensorflow as tf
|
|
if is_torch_available():
|
|
import torch
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
SPECIAL_TOKENS_MAP_FILE = "special_tokens_map.json"
|
|
ADDED_TOKENS_FILE = "added_tokens.json"
|
|
TOKENIZER_CONFIG_FILE = "tokenizer_config.json"
|
|
|
|
|
|
# Define type aliases
|
|
TextInput = str
|
|
TextPairInput = Tuple[str, str]
|
|
PreTokenizedInput = List[str]
|
|
PreTokenizedInputPair = Tuple[List[str], List[str]]
|
|
|
|
|
|
def flatten(x: Sequence):
|
|
"""
|
|
Flatten the provided (potentially nested) sequence
|
|
|
|
Args:
|
|
x (Sequence): Potentially nested sequence to flatten
|
|
|
|
Returns:
|
|
list: Flattened sequence
|
|
"""
|
|
|
|
return functools.reduce(operator.iconcat, x, [])
|
|
|
|
|
|
@contextmanager
|
|
def truncate_and_pad(
|
|
tokenizer: BaseTokenizer,
|
|
max_length: int,
|
|
stride: int,
|
|
strategy: str,
|
|
pad_to_max_length: bool,
|
|
padding_side: str,
|
|
pad_token_id: int,
|
|
pad_token_type_id: int,
|
|
pad_token: str,
|
|
):
|
|
"""
|
|
This contextmanager is in charge of defining the truncation and the padding strategies and then
|
|
restore the tokenizer settings afterwards.
|
|
|
|
This contextmanager assumes the provider tokenizer has no padding / truncation strategy
|
|
before the managed section. If your tokenizer set a padding / truncation strategy before,
|
|
then it will be reset to no padding/truncation when exiting the managed section.
|
|
|
|
Args:
|
|
tokenizer (BaseTokenizer): The tokenizer which will be used
|
|
max_length (int): The maximum size of the sequence
|
|
stride (int): The stride to use when handling overflow
|
|
strategy (str): Overflowing logic to use
|
|
pad_to_max_length (bool): Boolean indicating if the output needs to be padded up to max_length
|
|
padding_side (str): "left" or "right" indicating the direction the output sequence will be padded
|
|
pad_token_id (int): The integer representation of the padding token to use
|
|
pad_token_type_id (int): The integer representation of the padding token type to use
|
|
pad_token (str): The string representation of the padding token to use
|
|
|
|
Returns:
|
|
|
|
"""
|
|
|
|
# Handle all the truncation and padding stuff
|
|
if max_length is not None:
|
|
tokenizer.enable_truncation(max_length, stride=stride, strategy=strategy)
|
|
|
|
if pad_to_max_length and (pad_token and pad_token_id >= 0):
|
|
tokenizer.enable_padding(
|
|
max_length=max_length,
|
|
direction=padding_side,
|
|
pad_id=pad_token_id,
|
|
pad_type_id=pad_token_type_id,
|
|
pad_token=pad_token,
|
|
)
|
|
elif pad_to_max_length:
|
|
logger.warning(
|
|
"Disabled padding because no padding token set (pad_token: {}, pad_token_id: {}).\n"
|
|
"To remove this error, you can add a new pad token and then resize model embedding:\n"
|
|
"\ttokenizer.pad_token = '<PAD>'\n\tmodel.resize_token_embeddings(len(tokenizer))".format(
|
|
pad_token, pad_token_id
|
|
)
|
|
)
|
|
|
|
yield
|
|
|
|
if max_length is not None:
|
|
tokenizer.no_truncation()
|
|
|
|
if pad_to_max_length and (pad_token and pad_token_id >= 0):
|
|
tokenizer.no_padding()
|
|
|
|
|
|
class BatchEncoding(UserDict):
|
|
"""
|
|
Data structure derived from Dictionary holding all the required information to forward through
|
|
a model.
|
|
|
|
In addition, this structure expose utility methods to map from word/char space to token space.
|
|
"""
|
|
|
|
def __init__(self, data: dict, encoding: Optional[Union[Encoding, Sequence[Encoding]]] = None):
|
|
super().__init__(data)
|
|
|
|
if isinstance(encoding, Encoding):
|
|
encoding = [encoding]
|
|
|
|
self._encodings = encoding
|
|
|
|
def __getitem__(self, item: Union[int, str]) -> Encoding:
|
|
if isinstance(item, str):
|
|
return self.data[item]
|
|
elif self._encodings is not None:
|
|
return self._encodings[item]
|
|
else:
|
|
raise KeyError("int index is supported only on {} from a Rust tokenizer".format(type(self).__name__))
|
|
|
|
def __getattr__(self, item: str):
|
|
return self.data[item]
|
|
|
|
@property
|
|
def encodings(self) -> Optional[List[Encoding]]:
|
|
"""
|
|
Return the list all encoding from the tokenization process
|
|
|
|
Returns: List[Encoding] or None if input was tokenized through Python tokenizer
|
|
"""
|
|
return self._encodings
|
|
|
|
def keys(self):
|
|
return self.data.keys()
|
|
|
|
def values(self):
|
|
return self.data.values()
|
|
|
|
def items(self):
|
|
return self.data.items()
|
|
|
|
def char_to_token_offsets(self, sentence: int, char: int) -> Tuple[int, int]:
|
|
"""
|
|
Find the Offsets of the token containing the character at the specified position
|
|
|
|
Args:
|
|
sentence: Index of the sentence relative to the batch provided to the tokenizer
|
|
char: Char index to get the relative token offsets
|
|
|
|
Returns:
|
|
tuple: (token start, token end)
|
|
|
|
"""
|
|
|
|
if not self._encodings:
|
|
raise ValueError("char_to_token_offsets() is not available when using Python based tokenizers")
|
|
return self[sentence].char_to_token_offsets(char)
|
|
|
|
def char_to_token(self, sentence: int, char: int) -> int:
|
|
"""
|
|
Return the index of the token at position of the given char.
|
|
|
|
Args:
|
|
sentence (int): Index of the sentence relative to the batch provided to the tokenizer
|
|
char (int): Char index to get the relative token offsets
|
|
|
|
Returns:
|
|
int: Integer referring to the position of the token in the returned set of tokens for the sentence
|
|
"""
|
|
|
|
if not self._encodings:
|
|
raise ValueError("char_to_token() is not available when using Python based tokenizers")
|
|
return self[sentence].char_to_token(char)
|
|
|
|
def char_to_word_offsets(self, sentence: int, char: int) -> Tuple[int, int]:
|
|
"""
|
|
Find the Offsets of the word containing the character at the specified position
|
|
|
|
Args:
|
|
sentence (int): Index of the sentence relative to the batch provided to the tokenizer
|
|
char (int): Char index to get the relative token offsets
|
|
|
|
Returns:
|
|
tuple: (word start, word end) representing the first and last characters of the word
|
|
"""
|
|
|
|
if not self._encodings:
|
|
raise ValueError("char_to_word_offsets() is not available when using Python based tokenizers")
|
|
return self[sentence].char_to_word_offsets(char)
|
|
|
|
def token_to_word_offsets(self, sentence: int, index: int) -> Optional[Tuple[int, int]]:
|
|
"""
|
|
Find the Offsets of the word containing the token at the given index
|
|
|
|
Args:
|
|
sentence (int): Index of the sentence relative to the batch provided to the tokenizer
|
|
index (int): Index of the token to map to the original word offsets
|
|
|
|
Returns:
|
|
Optional[tuple]: (word start, word end) or None
|
|
"""
|
|
|
|
if not self._encodings:
|
|
raise ValueError("token_to_word_offsets() is not available when using Python based tokenizers")
|
|
return self[sentence].token_to_word_offsets(index)
|
|
|
|
|
|
class SpecialTokensMixin:
|
|
SPECIAL_TOKENS_ATTRIBUTES = [
|
|
"bos_token",
|
|
"eos_token",
|
|
"unk_token",
|
|
"sep_token",
|
|
"pad_token",
|
|
"cls_token",
|
|
"mask_token",
|
|
"additional_special_tokens",
|
|
]
|
|
|
|
def __init__(self, **kwargs):
|
|
|
|
self._bos_token = None
|
|
self._eos_token = None
|
|
self._unk_token = None
|
|
self._sep_token = None
|
|
self._pad_token = None
|
|
self._cls_token = None
|
|
self._mask_token = None
|
|
self._pad_token_type_id = 0
|
|
self._additional_special_tokens = []
|
|
|
|
for key, value in kwargs.items():
|
|
if key in self.SPECIAL_TOKENS_ATTRIBUTES:
|
|
if key == "additional_special_tokens":
|
|
assert isinstance(value, (list, tuple)) and all(isinstance(t, str) for t in value)
|
|
elif isinstance(value, AddedToken):
|
|
setattr(self, key, str(value))
|
|
elif isinstance(value, str):
|
|
setattr(self, key, value)
|
|
else:
|
|
raise TypeError(
|
|
"special token {} has to be either str or AddedToken but got: {}".format(key, type(value))
|
|
)
|
|
|
|
@property
|
|
def bos_token(self):
|
|
""" Beginning of sentence token (string). Log an error if used while not having been set. """
|
|
if self._bos_token is None:
|
|
logger.error("Using bos_token, but it is not set yet.")
|
|
return self._bos_token
|
|
|
|
@property
|
|
def eos_token(self):
|
|
""" End of sentence token (string). Log an error if used while not having been set. """
|
|
if self._eos_token is None:
|
|
logger.error("Using eos_token, but it is not set yet.")
|
|
return self._eos_token
|
|
|
|
@property
|
|
def unk_token(self):
|
|
""" Unknown token (string). Log an error if used while not having been set. """
|
|
if self._unk_token is None:
|
|
logger.error("Using unk_token, but it is not set yet.")
|
|
return self._unk_token
|
|
|
|
@property
|
|
def sep_token(self):
|
|
""" Separation token (string). E.g. separate context and query in an input sequence. Log an error if used while not having been set. """
|
|
if self._sep_token is None:
|
|
logger.error("Using sep_token, but it is not set yet.")
|
|
return self._sep_token
|
|
|
|
@property
|
|
def pad_token(self):
|
|
""" Padding token (string). Log an error if used while not having been set. """
|
|
if self._pad_token is None:
|
|
logger.error("Using pad_token, but it is not set yet.")
|
|
return self._pad_token
|
|
|
|
@property
|
|
def cls_token(self):
|
|
""" Classification token (string). E.g. to extract a summary of an input sequence leveraging self-attention along the full depth of the model. Log an error if used while not having been set. """
|
|
if self._cls_token is None:
|
|
logger.error("Using cls_token, but it is not set yet.")
|
|
return self._cls_token
|
|
|
|
@property
|
|
def mask_token(self):
|
|
""" Mask token (string). E.g. when training a model with masked-language modeling. Log an error if used while not having been set. """
|
|
if self._mask_token is None:
|
|
logger.error("Using mask_token, but it is not set yet.")
|
|
return self._mask_token
|
|
|
|
@property
|
|
def additional_special_tokens(self):
|
|
""" All the additional special tokens you may want to use (list of strings). Log an error if used while not having been set. """
|
|
if self._additional_special_tokens is None:
|
|
logger.error("Using additional_special_tokens, but it is not set yet.")
|
|
return self._additional_special_tokens
|
|
|
|
@bos_token.setter
|
|
def bos_token(self, value):
|
|
self._bos_token = value
|
|
|
|
@eos_token.setter
|
|
def eos_token(self, value):
|
|
self._eos_token = value
|
|
|
|
@unk_token.setter
|
|
def unk_token(self, value):
|
|
self._unk_token = value
|
|
|
|
@sep_token.setter
|
|
def sep_token(self, value):
|
|
self._sep_token = value
|
|
|
|
@pad_token.setter
|
|
def pad_token(self, value):
|
|
self._pad_token = value
|
|
|
|
@cls_token.setter
|
|
def cls_token(self, value):
|
|
self._cls_token = value
|
|
|
|
@mask_token.setter
|
|
def mask_token(self, value):
|
|
self._mask_token = value
|
|
|
|
@property
|
|
def bos_token_id(self):
|
|
""" Id of the beginning of sentence token in the vocabulary. Log an error if used while not having been set. """
|
|
return self.convert_tokens_to_ids(self.bos_token)
|
|
|
|
@property
|
|
def eos_token_id(self):
|
|
""" Id of the end of sentence token in the vocabulary. Log an error if used while not having been set. """
|
|
return self.convert_tokens_to_ids(self.eos_token)
|
|
|
|
@property
|
|
def unk_token_id(self):
|
|
""" Id of the unknown token in the vocabulary. Log an error if used while not having been set. """
|
|
return self.convert_tokens_to_ids(self.unk_token)
|
|
|
|
@property
|
|
def sep_token_id(self):
|
|
""" Id of the separation token in the vocabulary. E.g. separate context and query in an input sequence. Log an error if used while not having been set. """
|
|
return self.convert_tokens_to_ids(self.sep_token)
|
|
|
|
@property
|
|
def pad_token_id(self):
|
|
""" Id of the padding token in the vocabulary. Log an error if used while not having been set. """
|
|
return self.convert_tokens_to_ids(self.pad_token)
|
|
|
|
@property
|
|
def pad_token_type_id(self):
|
|
""" Id of the padding token type in the vocabulary."""
|
|
return self._pad_token_type_id
|
|
|
|
@property
|
|
def cls_token_id(self):
|
|
""" Id of the classification token in the vocabulary. E.g. to extract a summary of an input sequence leveraging self-attention along the full depth of the model. Log an error if used while not having been set. """
|
|
return self.convert_tokens_to_ids(self.cls_token)
|
|
|
|
@property
|
|
def mask_token_id(self):
|
|
""" Id of the mask token in the vocabulary. E.g. when training a model with masked-language modeling. Log an error if used while not having been set. """
|
|
return self.convert_tokens_to_ids(self.mask_token)
|
|
|
|
@property
|
|
def additional_special_tokens_ids(self):
|
|
""" Ids of all the additional special tokens in the vocabulary (list of integers). Log an error if used while not having been set. """
|
|
return self.convert_tokens_to_ids(self.additional_special_tokens)
|
|
|
|
@property
|
|
def special_tokens_map(self):
|
|
""" A dictionary mapping special token class attribute (cls_token, unk_token...) to their
|
|
values ('<unk>', '<cls>'...)
|
|
"""
|
|
set_attr = {}
|
|
for attr in self.SPECIAL_TOKENS_ATTRIBUTES:
|
|
attr_value = getattr(self, "_" + attr)
|
|
if attr_value:
|
|
set_attr[attr] = attr_value
|
|
return set_attr
|
|
|
|
@property
|
|
def all_special_tokens(self):
|
|
""" List all the special tokens ('<unk>', '<cls>'...) mapped to class attributes
|
|
(cls_token, unk_token...).
|
|
"""
|
|
all_toks = []
|
|
set_attr = self.special_tokens_map
|
|
for attr_value in set_attr.values():
|
|
all_toks = all_toks + (list(attr_value) if isinstance(attr_value, (list, tuple)) else [attr_value])
|
|
all_toks = list(set(all_toks))
|
|
return all_toks
|
|
|
|
@property
|
|
def all_special_ids(self):
|
|
""" List the vocabulary indices of the special tokens ('<unk>', '<cls>'...) mapped to
|
|
class attributes (cls_token, unk_token...).
|
|
"""
|
|
all_toks = self.all_special_tokens
|
|
all_ids = self.convert_tokens_to_ids(all_toks)
|
|
return all_ids
|
|
|
|
@additional_special_tokens.setter
|
|
def additional_special_tokens(self, value):
|
|
self._additional_special_tokens = value
|
|
|
|
|
|
class PreTrainedTokenizer(SpecialTokensMixin):
|
|
""" Base class for all tokenizers.
|
|
Handle all the shared methods for tokenization and special tokens as well as methods downloading/caching/loading pretrained tokenizers as well as adding tokens to the vocabulary.
|
|
|
|
This class also contain the added tokens in a unified way on top of all tokenizers so we don't have to handle the specific vocabulary augmentation methods of the various underlying dictionary structures (BPE, sentencepiece...).
|
|
|
|
Class attributes (overridden by derived classes):
|
|
|
|
- ``vocab_files_names``: a python ``dict`` with, as keys, the ``__init__`` keyword name of each vocabulary file required by the model, and as associated values, the filename for saving the associated file (string).
|
|
- ``pretrained_vocab_files_map``: a python ``dict of dict`` the high-level keys being the ``__init__`` keyword name of each vocabulary file required by the model, the low-level being the `short-cut-names` (string) of the pretrained models with, as associated values, the `url` (string) to the associated pretrained vocabulary file.
|
|
- ``max_model_input_sizes``: a python ``dict`` with, as keys, the `short-cut-names` (string) of the pretrained models, and as associated values, the maximum length of the sequence inputs of this model, or None if the model has no maximum input size.
|
|
- ``pretrained_init_configuration``: a python ``dict`` with, as keys, the `short-cut-names` (string) of the pretrained models, and as associated values, a dictionnary of specific arguments to pass to the ``__init__``method of the tokenizer class for this pretrained model when loading the tokenizer with the ``from_pretrained()`` method.
|
|
|
|
Parameters:
|
|
|
|
- ``bos_token``: (`Optional`) string: a beginning of sentence token. Will be associated to ``self.bos_token`` and ``self.bos_token_id``
|
|
|
|
- ``eos_token``: (`Optional`) string: an end of sentence token. Will be associated to ``self.eos_token`` and ``self.eos_token_id``
|
|
|
|
- ``unk_token``: (`Optional`) string: an unknown token. Will be associated to ``self.unk_token`` and ``self.unk_token_id``
|
|
|
|
- ``sep_token``: (`Optional`) string: a separation token (e.g. to separate context and query in an input sequence). Will be associated to ``self.sep_token`` and ``self.sep_token_id``
|
|
|
|
- ``pad_token``: (`Optional`) string: a padding token. Will be associated to ``self.pad_token`` and ``self.pad_token_id``
|
|
|
|
- ``cls_token``: (`Optional`) string: a classification token (e.g. to extract a summary of an input sequence leveraging self-attention along the full depth of the model). Will be associated to ``self.cls_token`` and ``self.cls_token_id``
|
|
|
|
- ``mask_token``: (`Optional`) string: a masking token (e.g. when training a model with masked-language modeling). Will be associated to ``self.mask_token`` and ``self.mask_token_id``
|
|
|
|
- ``additional_special_tokens``: (`Optional`) list: a list of additional special tokens. Adding all special tokens here ensure they won't be split by the tokenization process. Will be associated to ``self.additional_special_tokens`` and ``self.additional_special_tokens_ids``
|
|
"""
|
|
|
|
vocab_files_names = {}
|
|
pretrained_vocab_files_map = {}
|
|
pretrained_init_configuration = {}
|
|
max_model_input_sizes = {}
|
|
model_input_names = ["token_type_ids", "attention_mask"]
|
|
|
|
padding_side = "right"
|
|
|
|
NO_PAD_TOKEN_FOR_BATCH_MSG = (
|
|
"No padding token is set for this model, therefore no batch can be made with uneven "
|
|
"sequences. Set a padding token or adjust the lengths of the sequences building the "
|
|
"batch so that every sequence is of the same length."
|
|
)
|
|
|
|
UNEVEN_SEQUENCES_FOR_BATCH_MSG = (
|
|
"The sequences building the batch are not of the same size, no tensor "
|
|
"can be built. Set `pad_to_max_length=True` to pad the smaller sequences"
|
|
"up to the larger sequence's length."
|
|
)
|
|
|
|
@property
|
|
def vocab_size(self) -> int:
|
|
""" Size of the base vocabulary (without the added tokens) """
|
|
raise NotImplementedError
|
|
|
|
@property
|
|
def is_fast(self):
|
|
return False
|
|
|
|
def get_vocab(self):
|
|
""" Returns the vocabulary as a dict of {token: index} pairs. `tokenizer.get_vocab()[token]` is equivalent to `tokenizer.convert_tokens_to_ids(token)` when `token` is in the vocab. """
|
|
raise NotImplementedError()
|
|
|
|
def __init__(self, max_len=None, **kwargs):
|
|
|
|
super().__init__(**kwargs)
|
|
|
|
self.max_len = max_len if max_len is not None else int(1e12)
|
|
|
|
# Padding side is right by default and over-riden in subclasses. If specified in the kwargs, it is changed.
|
|
self.padding_side = kwargs.pop("padding_side", self.padding_side)
|
|
self.model_input_names = kwargs.pop("model_input_names", self.model_input_names)
|
|
|
|
# Added tokens
|
|
self.added_tokens_encoder = {}
|
|
self.unique_added_tokens_encoder = set()
|
|
self.added_tokens_decoder = {}
|
|
|
|
# inputs and kwargs for saving and re-loading (see ``from_pretrained`` and ``save_pretrained``)
|
|
self.init_inputs = ()
|
|
self.init_kwargs = {}
|
|
|
|
def __len__(self):
|
|
""" Size of the full vocabulary with the added tokens """
|
|
return self.vocab_size + len(self.added_tokens_encoder)
|
|
|
|
@classmethod
|
|
def from_pretrained(cls, *inputs, **kwargs):
|
|
r"""
|
|
Instantiate a :class:`~transformers.PreTrainedTokenizer` (or a derived class) from a predefined tokenizer.
|
|
|
|
Args:
|
|
pretrained_model_name_or_path: either:
|
|
|
|
- a string with the `shortcut name` of a predefined tokenizer to load from cache or download, e.g.: ``bert-base-uncased``.
|
|
- a string with the `identifier name` of a predefined tokenizer that was user-uploaded to our S3, e.g.: ``dbmdz/bert-base-german-cased``.
|
|
- a path to a `directory` containing vocabulary files required by the tokenizer, for instance saved using the :func:`~transformers.PreTrainedTokenizer.save_pretrained` method, e.g.: ``./my_model_directory/``.
|
|
- (not applicable to all derived classes, deprecated) a path or url to a single saved vocabulary file if and only if the tokenizer only requires a single vocabulary file (e.g. Bert, XLNet), e.g.: ``./my_model_directory/vocab.txt``.
|
|
|
|
cache_dir: (`optional`) string:
|
|
Path to a directory in which a downloaded predefined tokenizer vocabulary files should be cached if the standard cache should not be used.
|
|
|
|
force_download: (`optional`) boolean, default False:
|
|
Force to (re-)download the vocabulary files and override the cached versions if they exists.
|
|
|
|
resume_download: (`optional`) boolean, default False:
|
|
Do not delete incompletely recieved file. Attempt to resume the download if such a file exists.
|
|
|
|
proxies: (`optional`) dict, default None:
|
|
A dictionary of proxy servers to use by protocol or endpoint, e.g.: {'http': 'foo.bar:3128', 'http://hostname': 'foo.bar:4012'}.
|
|
The proxies are used on each request.
|
|
|
|
inputs: (`optional`) positional arguments: will be passed to the Tokenizer ``__init__`` method.
|
|
|
|
kwargs: (`optional`) keyword arguments: will be passed to the Tokenizer ``__init__`` method. Can be used to set special tokens like ``bos_token``, ``eos_token``, ``unk_token``, ``sep_token``, ``pad_token``, ``cls_token``, ``mask_token``, ``additional_special_tokens``. See parameters in the doc string of :class:`~transformers.PreTrainedTokenizer` for details.
|
|
|
|
Examples::
|
|
|
|
# We can't instantiate directly the base class `PreTrainedTokenizer` so let's show our examples on a derived class: BertTokenizer
|
|
|
|
# Download vocabulary from S3 and cache.
|
|
tokenizer = BertTokenizer.from_pretrained('bert-base-uncased')
|
|
|
|
# Download vocabulary from S3 (user-uploaded) and cache.
|
|
tokenizer = BertTokenizer.from_pretrained('dbmdz/bert-base-german-cased')
|
|
|
|
# If vocabulary files are in a directory (e.g. tokenizer was saved using `save_pretrained('./test/saved_model/')`)
|
|
tokenizer = BertTokenizer.from_pretrained('./test/saved_model/')
|
|
|
|
# If the tokenizer uses a single vocabulary file, you can point directly to this file
|
|
tokenizer = BertTokenizer.from_pretrained('./test/saved_model/my_vocab.txt')
|
|
|
|
# You can link tokens to special vocabulary when instantiating
|
|
tokenizer = BertTokenizer.from_pretrained('bert-base-uncased', unk_token='<unk>')
|
|
# You should be sure '<unk>' is in the vocabulary when doing that.
|
|
# Otherwise use tokenizer.add_special_tokens({'unk_token': '<unk>'}) instead)
|
|
assert tokenizer.unk_token == '<unk>'
|
|
|
|
"""
|
|
return cls._from_pretrained(*inputs, **kwargs)
|
|
|
|
@classmethod
|
|
def _from_pretrained(cls, pretrained_model_name_or_path, *init_inputs, **kwargs):
|
|
cache_dir = kwargs.pop("cache_dir", None)
|
|
force_download = kwargs.pop("force_download", False)
|
|
resume_download = kwargs.pop("resume_download", False)
|
|
proxies = kwargs.pop("proxies", None)
|
|
local_files_only = kwargs.pop("local_files_only", False)
|
|
|
|
s3_models = list(cls.max_model_input_sizes.keys())
|
|
vocab_files = {}
|
|
init_configuration = {}
|
|
if pretrained_model_name_or_path in s3_models:
|
|
# Get the vocabulary from AWS S3 bucket
|
|
for file_id, map_list in cls.pretrained_vocab_files_map.items():
|
|
vocab_files[file_id] = map_list[pretrained_model_name_or_path]
|
|
if (
|
|
cls.pretrained_init_configuration
|
|
and pretrained_model_name_or_path in cls.pretrained_init_configuration
|
|
):
|
|
init_configuration = cls.pretrained_init_configuration[pretrained_model_name_or_path].copy()
|
|
else:
|
|
# Get the vocabulary from local files
|
|
logger.info(
|
|
"Model name '{}' not found in model shortcut name list ({}). "
|
|
"Assuming '{}' is a path, a model identifier, or url to a directory containing tokenizer files.".format(
|
|
pretrained_model_name_or_path, ", ".join(s3_models), pretrained_model_name_or_path
|
|
)
|
|
)
|
|
|
|
if os.path.isfile(pretrained_model_name_or_path) or is_remote_url(pretrained_model_name_or_path):
|
|
if len(cls.vocab_files_names) > 1:
|
|
raise ValueError(
|
|
"Calling {}.from_pretrained() with the path to a single file or url is not supported."
|
|
"Use a model identifier or the path to a directory instead.".format(cls.__name__)
|
|
)
|
|
logger.warning(
|
|
"Calling {}.from_pretrained() with the path to a single file or url is deprecated".format(
|
|
cls.__name__
|
|
)
|
|
)
|
|
file_id = list(cls.vocab_files_names.keys())[0]
|
|
vocab_files[file_id] = pretrained_model_name_or_path
|
|
else:
|
|
# At this point pretrained_model_name_or_path is either a directory or a model identifier name
|
|
additional_files_names = {
|
|
"added_tokens_file": ADDED_TOKENS_FILE,
|
|
"special_tokens_map_file": SPECIAL_TOKENS_MAP_FILE,
|
|
"tokenizer_config_file": TOKENIZER_CONFIG_FILE,
|
|
}
|
|
# Look for the tokenizer main vocabulary files + the additional tokens files
|
|
for file_id, file_name in {**cls.vocab_files_names, **additional_files_names}.items():
|
|
if os.path.isdir(pretrained_model_name_or_path):
|
|
full_file_name = os.path.join(pretrained_model_name_or_path, file_name)
|
|
if not os.path.exists(full_file_name):
|
|
logger.info("Didn't find file {}. We won't load it.".format(full_file_name))
|
|
full_file_name = None
|
|
else:
|
|
full_file_name = hf_bucket_url(pretrained_model_name_or_path, postfix=file_name)
|
|
|
|
vocab_files[file_id] = full_file_name
|
|
|
|
# Get files from url, cache, or disk depending on the case
|
|
try:
|
|
resolved_vocab_files = {}
|
|
for file_id, file_path in vocab_files.items():
|
|
if file_path is None:
|
|
resolved_vocab_files[file_id] = None
|
|
else:
|
|
resolved_vocab_files[file_id] = cached_path(
|
|
file_path,
|
|
cache_dir=cache_dir,
|
|
force_download=force_download,
|
|
proxies=proxies,
|
|
resume_download=resume_download,
|
|
local_files_only=local_files_only,
|
|
)
|
|
except EnvironmentError:
|
|
if pretrained_model_name_or_path in s3_models:
|
|
msg = "Couldn't reach server at '{}' to download vocabulary files."
|
|
else:
|
|
msg = (
|
|
"Model name '{}' was not found in tokenizers model name list ({}). "
|
|
"We assumed '{}' was a path or url to a directory containing vocabulary files "
|
|
"named {}, but couldn't find such vocabulary files at this path or url.".format(
|
|
pretrained_model_name_or_path,
|
|
", ".join(s3_models),
|
|
pretrained_model_name_or_path,
|
|
list(cls.vocab_files_names.values()),
|
|
)
|
|
)
|
|
|
|
raise EnvironmentError(msg)
|
|
|
|
if all(full_file_name is None for full_file_name in resolved_vocab_files.values()):
|
|
raise EnvironmentError(
|
|
"Model name '{}' was not found in tokenizers model name list ({}). "
|
|
"We assumed '{}' was a path, a model identifier, or url to a directory containing vocabulary files "
|
|
"named {} but couldn't find such vocabulary files at this path or url.".format(
|
|
pretrained_model_name_or_path,
|
|
", ".join(s3_models),
|
|
pretrained_model_name_or_path,
|
|
list(cls.vocab_files_names.values()),
|
|
)
|
|
)
|
|
|
|
for file_id, file_path in vocab_files.items():
|
|
if file_path == resolved_vocab_files[file_id]:
|
|
logger.info("loading file {}".format(file_path))
|
|
else:
|
|
logger.info("loading file {} from cache at {}".format(file_path, resolved_vocab_files[file_id]))
|
|
|
|
# Prepare tokenizer initialization kwargs
|
|
# Did we saved some inputs and kwargs to reload ?
|
|
tokenizer_config_file = resolved_vocab_files.pop("tokenizer_config_file", None)
|
|
if tokenizer_config_file is not None:
|
|
with open(tokenizer_config_file, encoding="utf-8") as tokenizer_config_handle:
|
|
init_kwargs = json.load(tokenizer_config_handle)
|
|
saved_init_inputs = init_kwargs.pop("init_inputs", ())
|
|
if not init_inputs:
|
|
init_inputs = saved_init_inputs
|
|
else:
|
|
init_kwargs = init_configuration
|
|
|
|
# Update with newly provided kwargs
|
|
init_kwargs.update(kwargs)
|
|
|
|
# Set max length if needed
|
|
if pretrained_model_name_or_path in cls.max_model_input_sizes:
|
|
# if we're using a pretrained model, ensure the tokenizer
|
|
# wont index sequences longer than the number of positional embeddings
|
|
max_len = cls.max_model_input_sizes[pretrained_model_name_or_path]
|
|
if max_len is not None and isinstance(max_len, (int, float)):
|
|
init_kwargs["max_len"] = min(init_kwargs.get("max_len", int(1e12)), max_len)
|
|
|
|
# Merge resolved_vocab_files arguments in init_kwargs.
|
|
added_tokens_file = resolved_vocab_files.pop("added_tokens_file", None)
|
|
special_tokens_map_file = resolved_vocab_files.pop("special_tokens_map_file", None)
|
|
for args_name, file_path in resolved_vocab_files.items():
|
|
if args_name not in init_kwargs:
|
|
init_kwargs[args_name] = file_path
|
|
if special_tokens_map_file is not None:
|
|
with open(special_tokens_map_file, encoding="utf-8") as special_tokens_map_handle:
|
|
special_tokens_map = json.load(special_tokens_map_handle)
|
|
for key, value in special_tokens_map.items():
|
|
if key not in init_kwargs:
|
|
init_kwargs[key] = value
|
|
|
|
# Instantiate tokenizer.
|
|
try:
|
|
tokenizer = cls(*init_inputs, **init_kwargs)
|
|
except OSError:
|
|
raise OSError(
|
|
"Unable to load vocabulary from file. "
|
|
"Please check that the provided vocabulary is accessible and not corrupted."
|
|
)
|
|
|
|
# Save inputs and kwargs for saving and re-loading with ``save_pretrained``
|
|
tokenizer.init_inputs = init_inputs
|
|
tokenizer.init_kwargs = init_kwargs
|
|
|
|
# update unique_added_tokens_encoder with special tokens for correct tokenization
|
|
tokenizer.unique_added_tokens_encoder.update(set(tokenizer.all_special_tokens))
|
|
|
|
# Add supplementary tokens.
|
|
if added_tokens_file is not None:
|
|
with open(added_tokens_file, encoding="utf-8") as added_tokens_handle:
|
|
added_tok_encoder = json.load(added_tokens_handle)
|
|
added_tok_decoder = {v: k for k, v in added_tok_encoder.items()}
|
|
tokenizer.added_tokens_encoder.update(added_tok_encoder)
|
|
tokenizer.added_tokens_decoder.update(added_tok_decoder)
|
|
tokenizer.unique_added_tokens_encoder.update(set(tokenizer.added_tokens_encoder.keys()))
|
|
|
|
return tokenizer
|
|
|
|
def save_pretrained(self, save_directory):
|
|
""" Save the tokenizer vocabulary files together with:
|
|
- added tokens,
|
|
- special-tokens-to-class-attributes-mapping,
|
|
- tokenizer instantiation positional and keywords inputs (e.g. do_lower_case for Bert).
|
|
|
|
This won't save modifications other than (added tokens and special token mapping) you may have
|
|
applied to the tokenizer after the instantiation (e.g. modifying tokenizer.do_lower_case after creation).
|
|
|
|
This method make sure the full tokenizer can then be re-loaded using the :func:`~transformers.PreTrainedTokenizer.from_pretrained` class method.
|
|
"""
|
|
if not os.path.isdir(save_directory):
|
|
logger.error("Saving directory ({}) should be a directory".format(save_directory))
|
|
return
|
|
|
|
special_tokens_map_file = os.path.join(save_directory, SPECIAL_TOKENS_MAP_FILE)
|
|
added_tokens_file = os.path.join(save_directory, ADDED_TOKENS_FILE)
|
|
tokenizer_config_file = os.path.join(save_directory, TOKENIZER_CONFIG_FILE)
|
|
|
|
tokenizer_config = copy.deepcopy(self.init_kwargs)
|
|
if len(self.init_inputs) > 0:
|
|
tokenizer_config["init_inputs"] = copy.deepcopy(self.init_inputs)
|
|
for file_id in self.vocab_files_names.keys():
|
|
tokenizer_config.pop(file_id, None)
|
|
|
|
with open(tokenizer_config_file, "w", encoding="utf-8") as f:
|
|
f.write(json.dumps(tokenizer_config, ensure_ascii=False))
|
|
|
|
with open(special_tokens_map_file, "w", encoding="utf-8") as f:
|
|
f.write(json.dumps(self.special_tokens_map, ensure_ascii=False))
|
|
|
|
if len(self.added_tokens_encoder) > 0:
|
|
with open(added_tokens_file, "w", encoding="utf-8") as f:
|
|
out_str = json.dumps(self.added_tokens_encoder, ensure_ascii=False)
|
|
f.write(out_str)
|
|
|
|
vocab_files = self.save_vocabulary(save_directory)
|
|
|
|
return vocab_files + (special_tokens_map_file, added_tokens_file)
|
|
|
|
def save_vocabulary(self, save_directory):
|
|
""" Save the tokenizer vocabulary to a directory. This method does *NOT* save added tokens
|
|
and special token mappings.
|
|
|
|
Please use :func:`~transformers.PreTrainedTokenizer.save_pretrained` `()` to save the full Tokenizer state if you want to reload it using the :func:`~transformers.PreTrainedTokenizer.from_pretrained` class method.
|
|
"""
|
|
raise NotImplementedError
|
|
|
|
def add_tokens(self, new_tokens):
|
|
"""
|
|
Add a list of new tokens to the tokenizer class. If the new tokens are not in the
|
|
vocabulary, they are added to it with indices starting from length of the current vocabulary.
|
|
|
|
Args:
|
|
new_tokens: string or list of string. Each string is a token to add. Tokens are only added if they are not already in the vocabulary (tested by checking if the tokenizer assign the index of the ``unk_token`` to them).
|
|
|
|
Returns:
|
|
Number of tokens added to the vocabulary.
|
|
|
|
Examples::
|
|
|
|
# Let's see how to increase the vocabulary of Bert model and tokenizer
|
|
tokenizer = BertTokenizer.from_pretrained('bert-base-uncased')
|
|
model = BertModel.from_pretrained('bert-base-uncased')
|
|
|
|
num_added_toks = tokenizer.add_tokens(['new_tok1', 'my_new-tok2'])
|
|
print('We have added', num_added_toks, 'tokens')
|
|
model.resize_token_embeddings(len(tokenizer)) # Notice: resize_token_embeddings expect to receive the full size of the new vocabulary, i.e. the length of the tokenizer.
|
|
"""
|
|
if not new_tokens:
|
|
return 0
|
|
|
|
if not isinstance(new_tokens, list):
|
|
new_tokens = [new_tokens]
|
|
|
|
to_add_tokens = []
|
|
for token in new_tokens:
|
|
assert isinstance(token, str)
|
|
if self.init_kwargs.get("do_lower_case", False) and token not in self.all_special_tokens:
|
|
token = token.lower()
|
|
if (
|
|
token != self.unk_token
|
|
and self.convert_tokens_to_ids(token) == self.convert_tokens_to_ids(self.unk_token)
|
|
and token not in to_add_tokens
|
|
):
|
|
to_add_tokens.append(token)
|
|
logger.info("Adding %s to the vocabulary", token)
|
|
|
|
added_tok_encoder = dict((tok, len(self) + i) for i, tok in enumerate(to_add_tokens))
|
|
added_tok_decoder = {v: k for k, v in added_tok_encoder.items()}
|
|
self.added_tokens_encoder.update(added_tok_encoder)
|
|
self.unique_added_tokens_encoder = set(self.added_tokens_encoder.keys()).union(set(self.all_special_tokens))
|
|
self.added_tokens_decoder.update(added_tok_decoder)
|
|
|
|
return len(to_add_tokens)
|
|
|
|
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))
|
|
|
|
def add_special_tokens(self, special_tokens_dict):
|
|
"""
|
|
Add a dictionary of special tokens (eos, pad, cls...) to the encoder and link them
|
|
to class attributes. If special tokens are NOT in the vocabulary, they are added
|
|
to it (indexed starting from the last index of the current vocabulary).
|
|
|
|
Using `add_special_tokens` will ensure your special tokens can be used in several ways:
|
|
|
|
- special tokens are carefully handled by the tokenizer (they are never split)
|
|
- you can easily refer to special tokens using tokenizer class attributes like `tokenizer.cls_token`. This makes it easy to develop model-agnostic training and fine-tuning scripts.
|
|
|
|
When possible, special tokens are already registered for provided pretrained models (ex: BertTokenizer cls_token is already registered to be '[CLS]' and XLM's one is also registered to be '</s>')
|
|
|
|
Args:
|
|
special_tokens_dict: dict of string. Keys should be in the list of predefined special attributes:
|
|
[``bos_token``, ``eos_token``, ``unk_token``, ``sep_token``, ``pad_token``, ``cls_token``, ``mask_token``,
|
|
``additional_special_tokens``].
|
|
|
|
Tokens are only added if they are not already in the vocabulary (tested by checking if the tokenizer assign the index of the ``unk_token`` to them).
|
|
|
|
Returns:
|
|
Number of tokens added to the vocabulary.
|
|
|
|
Examples::
|
|
|
|
# Let's see how to add a new classification token to GPT-2
|
|
tokenizer = GPT2Tokenizer.from_pretrained('gpt2')
|
|
model = GPT2Model.from_pretrained('gpt2')
|
|
|
|
special_tokens_dict = {'cls_token': '<CLS>'}
|
|
|
|
num_added_toks = tokenizer.add_special_tokens(special_tokens_dict)
|
|
print('We have added', num_added_toks, 'tokens')
|
|
model.resize_token_embeddings(len(tokenizer)) # Notice: resize_token_embeddings expect to receive the full size of the new vocabulary, i.e. the length of the tokenizer.
|
|
|
|
assert tokenizer.cls_token == '<CLS>'
|
|
"""
|
|
if not special_tokens_dict:
|
|
return 0
|
|
|
|
added_tokens = 0
|
|
for key, value in special_tokens_dict.items():
|
|
assert key in self.SPECIAL_TOKENS_ATTRIBUTES
|
|
if key == "additional_special_tokens":
|
|
assert isinstance(value, (list, tuple)) and all(isinstance(t, str) for t in value)
|
|
added_tokens += self.add_tokens(value)
|
|
else:
|
|
assert isinstance(value, str)
|
|
added_tokens += self.add_tokens([value])
|
|
logger.info("Assigning %s to the %s key of the tokenizer", value, key)
|
|
setattr(self, key, value)
|
|
|
|
return added_tokens
|
|
|
|
def tokenize(self, text: TextInput, **kwargs):
|
|
""" Converts a string in a sequence of tokens (string), using the tokenizer.
|
|
Split in words for word-based vocabulary or sub-words for sub-word-based
|
|
vocabularies (BPE/SentencePieces/WordPieces).
|
|
|
|
Take care of added tokens.
|
|
|
|
text: The sequence to be encoded.
|
|
add_prefix_space: Only applies to GPT-2 and RoBERTa tokenizers. When `True`, this ensures that the sequence
|
|
begins with an empty space. False by default except for when using RoBERTa with `add_special_tokens=True`.
|
|
**kwargs: passed to the `prepare_for_tokenization` preprocessing method.
|
|
"""
|
|
all_special_tokens = self.all_special_tokens
|
|
text = self.prepare_for_tokenization(text, **kwargs)
|
|
|
|
def lowercase_text(t):
|
|
# convert non-special tokens to lowercase
|
|
escaped_special_toks = [re.escape(s_tok) for s_tok in all_special_tokens]
|
|
pattern = r"(" + r"|".join(escaped_special_toks) + r")|" + r"(.+?)"
|
|
return re.sub(pattern, lambda m: m.groups()[0] or m.groups()[1].lower(), t)
|
|
|
|
if self.init_kwargs.get("do_lower_case", False):
|
|
text = lowercase_text(text)
|
|
|
|
def split_on_token(tok, text):
|
|
result = []
|
|
split_text = text.split(tok)
|
|
for i, sub_text in enumerate(split_text):
|
|
sub_text = sub_text.rstrip()
|
|
if i == 0 and not sub_text:
|
|
result += [tok]
|
|
elif i == len(split_text) - 1:
|
|
if sub_text:
|
|
result += [sub_text]
|
|
else:
|
|
pass
|
|
else:
|
|
if sub_text:
|
|
result += [sub_text]
|
|
result += [tok]
|
|
return result
|
|
|
|
def split_on_tokens(tok_list, text):
|
|
if not text.strip():
|
|
return []
|
|
if not tok_list:
|
|
return self._tokenize(text)
|
|
|
|
tokenized_text = []
|
|
text_list = [text]
|
|
for tok in tok_list:
|
|
tokenized_text = []
|
|
for sub_text in text_list:
|
|
if sub_text not in self.unique_added_tokens_encoder:
|
|
tokenized_text += split_on_token(tok, sub_text)
|
|
else:
|
|
tokenized_text += [sub_text]
|
|
text_list = tokenized_text
|
|
|
|
return list(
|
|
itertools.chain.from_iterable(
|
|
(
|
|
self._tokenize(token) if token not in self.unique_added_tokens_encoder else [token]
|
|
for token in tokenized_text
|
|
)
|
|
)
|
|
)
|
|
|
|
added_tokens = self.unique_added_tokens_encoder
|
|
tokenized_text = split_on_tokens(added_tokens, text)
|
|
return tokenized_text
|
|
|
|
def _tokenize(self, text, **kwargs):
|
|
""" Converts a string in a sequence of tokens (string), using the tokenizer.
|
|
Split in words for word-based vocabulary or sub-words for sub-word-based
|
|
vocabularies (BPE/SentencePieces/WordPieces).
|
|
|
|
Do NOT take care of added tokens.
|
|
"""
|
|
raise NotImplementedError
|
|
|
|
def convert_tokens_to_ids(self, tokens):
|
|
""" Converts a single token, or a sequence of tokens, (str) in a single integer id
|
|
(resp. a sequence of ids), using the vocabulary.
|
|
"""
|
|
if tokens is None:
|
|
return None
|
|
|
|
if isinstance(tokens, str):
|
|
return self._convert_token_to_id_with_added_voc(tokens)
|
|
|
|
ids = []
|
|
for token in tokens:
|
|
ids.append(self._convert_token_to_id_with_added_voc(token))
|
|
return ids
|
|
|
|
def _convert_token_to_id_with_added_voc(self, token):
|
|
if token is None:
|
|
return None
|
|
|
|
if token in self.added_tokens_encoder:
|
|
return self.added_tokens_encoder[token]
|
|
return self._convert_token_to_id(token)
|
|
|
|
def _convert_token_to_id(self, token):
|
|
raise NotImplementedError
|
|
|
|
def encode(
|
|
self,
|
|
text: TextInput,
|
|
text_pair: Optional[TextInput] = None,
|
|
add_special_tokens: bool = True,
|
|
max_length: Optional[int] = None,
|
|
stride: int = 0,
|
|
truncation_strategy: str = "longest_first",
|
|
pad_to_max_length: bool = False,
|
|
return_tensors: Optional[str] = None,
|
|
**kwargs
|
|
):
|
|
"""
|
|
Converts a string in a sequence of ids (integer), using the tokenizer and vocabulary.
|
|
|
|
Same as doing ``self.convert_tokens_to_ids(self.tokenize(text))``.
|
|
|
|
Args:
|
|
text (:obj:`str` or :obj:`List[str]`):
|
|
The first sequence to be encoded. This can be a string, a list of strings (tokenized string using
|
|
the `tokenize` method) or a list of integers (tokenized string ids using the `convert_tokens_to_ids`
|
|
method)
|
|
text_pair (:obj:`str` or :obj:`List[str]`, `optional`, defaults to :obj:`None`):
|
|
Optional second sequence to be encoded. This can be a string, a list of strings (tokenized
|
|
string using the `tokenize` method) or a list of integers (tokenized string ids using the
|
|
`convert_tokens_to_ids` method)
|
|
add_special_tokens (:obj:`bool`, `optional`, defaults to :obj:`True`):
|
|
If set to ``True``, the sequences will be encoded with the special tokens relative
|
|
to their model.
|
|
max_length (:obj:`int`, `optional`, defaults to :obj:`None`):
|
|
If set to a number, will limit the total sequence returned so that it has a maximum length.
|
|
If there are overflowing tokens, those will be added to the returned dictionary
|
|
stride (:obj:`int`, `optional`, defaults to ``0``):
|
|
If set to a number along with max_length, the overflowing tokens returned will contain some tokens
|
|
from the main sequence returned. The value of this argument defines the number of additional tokens.
|
|
truncation_strategy (:obj:`str`, `optional`, defaults to `longest_first`):
|
|
String selected in the following options:
|
|
|
|
- 'longest_first' (default) Iteratively reduce the inputs sequence until the input is under max_length
|
|
starting from the longest one at each token (when there is a pair of input sequences)
|
|
- 'only_first': Only truncate the first sequence
|
|
- 'only_second': Only truncate the second sequence
|
|
- 'do_not_truncate': Does not truncate (raise an error if the input sequence is longer than max_length)
|
|
pad_to_max_length (:obj:`bool`, `optional`, defaults to :obj:`False`):
|
|
If set to True, the returned sequences will be padded according to the model's padding side and
|
|
padding index, up to their max length. If no max length is specified, the padding is done up to the
|
|
model's max length. The tokenizer padding sides are handled by the class attribute `padding_side`
|
|
which can be set to the following strings:
|
|
|
|
- 'left': pads on the left of the sequences
|
|
- 'right': pads on the right of the sequences
|
|
Defaults to False: no padding.
|
|
return_tensors (:obj:`str`, `optional`, defaults to :obj:`None`):
|
|
Can be set to 'tf' or 'pt' to return respectively TensorFlow :obj:`tf.constant`
|
|
or PyTorch :obj:`torch.Tensor` instead of a list of python integers.
|
|
**kwargs: passed to the `self.tokenize()` method
|
|
"""
|
|
encoded_inputs = self.encode_plus(
|
|
text,
|
|
text_pair=text_pair,
|
|
max_length=max_length,
|
|
add_special_tokens=add_special_tokens,
|
|
stride=stride,
|
|
truncation_strategy=truncation_strategy,
|
|
pad_to_max_length=pad_to_max_length,
|
|
return_tensors=return_tensors,
|
|
**kwargs,
|
|
)
|
|
|
|
return encoded_inputs["input_ids"]
|
|
|
|
def encode_plus(
|
|
self,
|
|
text: TextInput,
|
|
text_pair: Optional[TextInput] = None,
|
|
add_special_tokens: bool = True,
|
|
max_length: Optional[int] = None,
|
|
stride: int = 0,
|
|
truncation_strategy: str = "longest_first",
|
|
pad_to_max_length: bool = False,
|
|
is_pretokenized: bool = False,
|
|
return_tensors: Optional[str] = None,
|
|
return_token_type_ids: Optional[bool] = None,
|
|
return_attention_mask: Optional[bool] = None,
|
|
return_overflowing_tokens: bool = False,
|
|
return_special_tokens_mask: bool = False,
|
|
return_offsets_mapping: bool = False,
|
|
**kwargs
|
|
) -> BatchEncoding:
|
|
"""
|
|
Returns a dictionary containing the encoded sequence or sequence pair and additional information:
|
|
the mask for sequence classification and the overflowing elements if a ``max_length`` is specified.
|
|
|
|
Args:
|
|
text (:obj:`str` or :obj:`List[str]`):
|
|
The first sequence to be encoded. This can be a string, a list of strings (tokenized string using
|
|
the `tokenize` method) or a list of integers (tokenized string ids using the `convert_tokens_to_ids`
|
|
method)
|
|
text_pair (:obj:`str` or :obj:`List[str]`, `optional`, defaults to :obj:`None`):
|
|
Optional second sequence to be encoded. This can be a string, a list of strings (tokenized
|
|
string using the `tokenize` method) or a list of integers (tokenized string ids using the
|
|
`convert_tokens_to_ids` method)
|
|
add_special_tokens (:obj:`bool`, `optional`, defaults to :obj:`True`):
|
|
If set to ``True``, the sequences will be encoded with the special tokens relative
|
|
to their model.
|
|
max_length (:obj:`int`, `optional`, defaults to :obj:`None`):
|
|
If set to a number, will limit the total sequence returned so that it has a maximum length.
|
|
If there are overflowing tokens, those will be added to the returned dictionary
|
|
stride (:obj:`int`, `optional`, defaults to ``0``):
|
|
If set to a number along with max_length, the overflowing tokens returned will contain some tokens
|
|
from the main sequence returned. The value of this argument defines the number of additional tokens.
|
|
truncation_strategy (:obj:`str`, `optional`, defaults to `longest_first`):
|
|
String selected in the following options:
|
|
|
|
- 'longest_first' (default) Iteratively reduce the inputs sequence until the input is under max_length
|
|
starting from the longest one at each token (when there is a pair of input sequences)
|
|
- 'only_first': Only truncate the first sequence
|
|
- 'only_second': Only truncate the second sequence
|
|
- 'do_not_truncate': Does not truncate (raise an error if the input sequence is longer than max_length)
|
|
pad_to_max_length (:obj:`bool`, `optional`, defaults to :obj:`False`):
|
|
If set to True, the returned sequences will be padded according to the model's padding side and
|
|
padding index, up to their max length. If no max length is specified, the padding is done up to the
|
|
model's max length. The tokenizer padding sides are handled by the class attribute `padding_side`
|
|
which can be set to the following strings:
|
|
|
|
- 'left': pads on the left of the sequences
|
|
- 'right': pads on the right of the sequences
|
|
Defaults to False: no padding.
|
|
is_pretokenized (:obj:`bool`, defaults to :obj:`False`):
|
|
Set to True to indicate the input is already tokenized
|
|
return_tensors (:obj:`str`, `optional`, defaults to :obj:`None`):
|
|
Can be set to 'tf' or 'pt' to return respectively TensorFlow :obj:`tf.constant`
|
|
or PyTorch :obj:`torch.Tensor` instead of a list of python integers.
|
|
return_token_type_ids (:obj:`bool`, `optional`, defaults to :obj:`None`):
|
|
Whether to return token type IDs. If left to the default, will return the token type IDs according
|
|
to the specific tokenizer's default, defined by the :obj:`return_outputs` attribute.
|
|
|
|
`What are token type IDs? <../glossary.html#token-type-ids>`_
|
|
return_attention_mask (:obj:`bool`, `optional`, defaults to :obj:`none`):
|
|
Whether to return the attention mask. If left to the default, will return the attention mask according
|
|
to the specific tokenizer's default, defined by the :obj:`return_outputs` attribute.
|
|
|
|
`What are attention masks? <../glossary.html#attention-mask>`__
|
|
return_overflowing_tokens (:obj:`bool`, `optional`, defaults to :obj:`False`):
|
|
Set to True to return overflowing token information (default False).
|
|
return_special_tokens_mask (:obj:`bool`, `optional`, defaults to :obj:`False`):
|
|
Set to True to return special tokens mask information (default False).
|
|
return_offsets_mapping (:obj:`bool`, `optional`, defaults to :obj:`False`):
|
|
Set to True to return (char_start, char_end) for each token (default False).
|
|
If using Python's tokenizer, this method will raise NotImplementedError. This one is only available on
|
|
Rust-based tokenizers inheriting from PreTrainedTokenizerFast.
|
|
**kwargs: passed to the `self.tokenize()` method
|
|
|
|
Return:
|
|
A Dictionary of shape::
|
|
|
|
{
|
|
input_ids: list[int],
|
|
token_type_ids: list[int] if return_token_type_ids is True (default)
|
|
attention_mask: list[int] if return_attention_mask is True (default)
|
|
overflowing_tokens: list[int] if a ``max_length`` is specified and return_overflowing_tokens is True
|
|
num_truncated_tokens: int if a ``max_length`` is specified and return_overflowing_tokens is True
|
|
special_tokens_mask: list[int] if ``add_special_tokens`` if set to ``True`` and return_special_tokens_mask is True
|
|
}
|
|
|
|
With the fields:
|
|
|
|
- ``input_ids``: list of token ids to be fed to a model
|
|
- ``token_type_ids``: list of token type ids to be fed to a model
|
|
- ``attention_mask``: list of indices specifying which tokens should be attended to by the model
|
|
- ``overflowing_tokens``: list of overflowing tokens if a max length is specified.
|
|
- ``num_truncated_tokens``: number of overflowing tokens a ``max_length`` is specified
|
|
- ``special_tokens_mask``: if adding special tokens, this is a list of [0, 1], with 0 specifying special added
|
|
tokens and 1 specifying sequence tokens.
|
|
"""
|
|
|
|
def get_input_ids(text):
|
|
if isinstance(text, str):
|
|
tokens = self.tokenize(text, add_special_tokens=add_special_tokens, **kwargs)
|
|
return self.convert_tokens_to_ids(tokens)
|
|
elif isinstance(text, (list, tuple)) and len(text) > 0 and isinstance(text[0], str):
|
|
return self.convert_tokens_to_ids(text)
|
|
elif isinstance(text, (list, tuple)) and len(text) > 0 and isinstance(text[0], int):
|
|
return text
|
|
else:
|
|
raise ValueError(
|
|
"Input is not valid. Should be a string, a list/tuple of strings or a list/tuple of integers."
|
|
)
|
|
|
|
if return_offsets_mapping:
|
|
raise NotImplementedError(
|
|
"return_offset_mapping is not available when using Python tokenizers."
|
|
"To use this feature, change your tokenizer to one deriving from "
|
|
"transformers.PreTrainedTokenizerFast."
|
|
"More information on available tokenizers at "
|
|
"https://github.com/huggingface/transformers/pull/2674"
|
|
)
|
|
|
|
# Throw an error if we can pad because there is no padding token
|
|
if pad_to_max_length and self.pad_token_id is None:
|
|
raise ValueError(
|
|
"Unable to set proper padding strategy as the tokenizer does not have a padding token. In this case please set the `pad_token` `(tokenizer.pad_token = tokenizer.eos_token e.g.)` or add a new pad token via the function add_special_tokens if you want to use a padding strategy"
|
|
)
|
|
|
|
first_ids = get_input_ids(text)
|
|
second_ids = get_input_ids(text_pair) if text_pair is not None else None
|
|
|
|
return self.prepare_for_model(
|
|
first_ids,
|
|
pair_ids=second_ids,
|
|
max_length=max_length,
|
|
pad_to_max_length=pad_to_max_length,
|
|
add_special_tokens=add_special_tokens,
|
|
stride=stride,
|
|
truncation_strategy=truncation_strategy,
|
|
return_tensors=return_tensors,
|
|
return_attention_mask=return_attention_mask,
|
|
return_token_type_ids=return_token_type_ids,
|
|
return_overflowing_tokens=return_overflowing_tokens,
|
|
return_special_tokens_mask=return_special_tokens_mask,
|
|
)
|
|
|
|
def batch_encode_plus(
|
|
self,
|
|
batch_text_or_text_pairs: Union[
|
|
List[TextInput], List[TextPairInput], List[PreTokenizedInput], List[PreTokenizedInputPair]
|
|
],
|
|
add_special_tokens: bool = True,
|
|
max_length: Optional[int] = None,
|
|
stride: int = 0,
|
|
truncation_strategy: str = "longest_first",
|
|
pad_to_max_length: bool = False,
|
|
is_pretokenized: bool = False,
|
|
return_tensors: Optional[str] = None,
|
|
return_token_type_ids: Optional[bool] = None,
|
|
return_attention_masks: Optional[bool] = None,
|
|
return_overflowing_tokens: bool = False,
|
|
return_special_tokens_masks: bool = False,
|
|
return_offsets_mapping: bool = False,
|
|
return_input_lengths: bool = False,
|
|
**kwargs
|
|
) -> BatchEncoding:
|
|
"""
|
|
Returns a dictionary containing the encoded sequence or sequence pair and additional information:
|
|
the mask for sequence classification and the overflowing elements if a ``max_length`` is specified.
|
|
|
|
Args:
|
|
batch_text_or_text_pairs (:obj:`List[str]` or :obj:`List[List[str]]`):
|
|
Batch of sequences or pair of sequences to be encoded.
|
|
This can be a list of string/string-sequences/int-sequences or a list of pair of
|
|
string/string-sequences/int-sequence (see details in encode_plus)
|
|
add_special_tokens (:obj:`bool`, `optional`, defaults to :obj:`True`):
|
|
If set to ``True``, the sequences will be encoded with the special tokens relative
|
|
to their model.
|
|
max_length (:obj:`int`, `optional`, defaults to :obj:`None`):
|
|
If set to a number, will limit the total sequence returned so that it has a maximum length.
|
|
If there are overflowing tokens, those will be added to the returned dictionary
|
|
stride (:obj:`int`, `optional`, defaults to ``0``):
|
|
If set to a number along with max_length, the overflowing tokens returned will contain some tokens
|
|
from the main sequence returned. The value of this argument defines the number of additional tokens.
|
|
truncation_strategy (:obj:`str`, `optional`, defaults to `longest_first`):
|
|
String selected in the following options:
|
|
|
|
- 'longest_first' (default) Iteratively reduce the inputs sequence until the input is under max_length
|
|
starting from the longest one at each token (when there is a pair of input sequences)
|
|
- 'only_first': Only truncate the first sequence
|
|
- 'only_second': Only truncate the second sequence
|
|
- 'do_not_truncate': Does not truncate (raise an error if the input sequence is longer than max_length)
|
|
pad_to_max_length (:obj:`bool`, `optional`, defaults to :obj:`False`):
|
|
If set to True, the returned sequences will be padded according to the model's padding side and
|
|
padding index, up to their max length. If no max length is specified, the padding is done up to the
|
|
model's max length. The tokenizer padding sides are handled by the class attribute `padding_side`
|
|
which can be set to the following strings:
|
|
|
|
- 'left': pads on the left of the sequences
|
|
- 'right': pads on the right of the sequences
|
|
Defaults to False: no padding.
|
|
is_pretokenized (:obj:`bool`, defaults to :obj:`False`):
|
|
Set to True to indicate the input is already tokenized
|
|
return_tensors (:obj:`str`, `optional`, defaults to :obj:`None`):
|
|
Can be set to 'tf' or 'pt' to return respectively TensorFlow :obj:`tf.constant`
|
|
or PyTorch :obj:`torch.Tensor` instead of a list of python integers.
|
|
return_token_type_ids (:obj:`bool`, `optional`, defaults to :obj:`None`):
|
|
Whether to return token type IDs. If left to the default, will return the token type IDs according
|
|
to the specific tokenizer's default, defined by the :obj:`return_outputs` attribute.
|
|
|
|
`What are token type IDs? <../glossary.html#token-type-ids>`_
|
|
return_attention_masks (:obj:`bool`, `optional`, defaults to :obj:`none`):
|
|
Whether to return the attention mask. If left to the default, will return the attention mask according
|
|
to the specific tokenizer's default, defined by the :obj:`return_outputs` attribute.
|
|
|
|
`What are attention masks? <../glossary.html#attention-mask>`__
|
|
return_overflowing_tokens (:obj:`bool`, `optional`, defaults to :obj:`False`):
|
|
Set to True to return overflowing token information (default False).
|
|
return_special_tokens_masks (:obj:`bool`, `optional`, defaults to :obj:`False`):
|
|
Set to True to return special tokens mask information (default False).
|
|
return_offsets_mapping (:obj:`bool`, `optional`, defaults to :obj:`False`):
|
|
Set to True to return (char_start, char_end) for each token (default False).
|
|
If using Python's tokenizer, this method will raise NotImplementedError. This one is only available on
|
|
Rust-based tokenizers inheriting from PreTrainedTokenizerFast.
|
|
return_input_lengths (:obj:`bool`, `optional`, defaults to :obj:`False`):
|
|
If set the resulting dictionary will include the length of each sample
|
|
**kwargs: passed to the `self.tokenize()` method
|
|
|
|
Return:
|
|
A Dictionary of shape::
|
|
|
|
{
|
|
input_ids: list[List[int]],
|
|
token_type_ids: list[List[int]] if return_token_type_ids is True (default)
|
|
attention_mask: list[List[int]] if return_attention_mask is True (default)
|
|
overflowing_tokens: list[List[int]] if a ``max_length`` is specified and return_overflowing_tokens is True
|
|
num_truncated_tokens: List[int] if a ``max_length`` is specified and return_overflowing_tokens is True
|
|
special_tokens_mask: list[List[int]] if ``add_special_tokens`` if set to ``True`` and return_special_tokens_mask is True
|
|
}
|
|
|
|
With the fields:
|
|
|
|
- ``input_ids``: list of token ids to be fed to a model
|
|
- ``token_type_ids``: list of token type ids to be fed to a model
|
|
- ``attention_mask``: list of indices specifying which tokens should be attended to by the model
|
|
- ``overflowing_tokens``: list of overflowing tokens if a max length is specified.
|
|
- ``num_truncated_tokens``: number of overflowing tokens a ``max_length`` is specified
|
|
- ``special_tokens_mask``: if adding special tokens, this is a list of [0, 1], with 0 specifying special added
|
|
tokens and 1 specifying sequence tokens.
|
|
"""
|
|
|
|
def get_input_ids(text):
|
|
if isinstance(text, str):
|
|
tokens = self.tokenize(text, add_special_tokens=add_special_tokens, **kwargs)
|
|
return self.convert_tokens_to_ids(tokens)
|
|
elif isinstance(text, (list, tuple)) and len(text) > 0 and isinstance(text[0], str):
|
|
return self.convert_tokens_to_ids(text)
|
|
elif isinstance(text, (list, tuple)) and len(text) > 0 and isinstance(text[0], int):
|
|
return text
|
|
else:
|
|
raise ValueError(
|
|
"Input is not valid. Should be a string, a list/tuple of strings or a list/tuple of integers."
|
|
)
|
|
|
|
# Throw an error if we can pad because there is no padding token
|
|
if pad_to_max_length and self.pad_token_id is None:
|
|
raise ValueError(
|
|
"Unable to set proper padding strategy as the tokenizer does not have a padding token. In this case please set the `pad_token` `(tokenizer.pad_token = tokenizer.eos_token e.g.)` or add a new pad token via the function add_special_tokens if you want to use a padding strategy"
|
|
)
|
|
|
|
if return_offsets_mapping:
|
|
raise NotImplementedError(
|
|
"return_offset_mapping is not available when using Python tokenizers."
|
|
"To use this feature, change your tokenizer to one deriving from "
|
|
"transformers.PreTrainedTokenizerFast."
|
|
"More information on available tokenizers at "
|
|
"https://github.com/huggingface/transformers/pull/2674"
|
|
)
|
|
|
|
input_ids = []
|
|
for ids_or_pair_ids in batch_text_or_text_pairs:
|
|
if isinstance(ids_or_pair_ids, (list, tuple)) and len(ids_or_pair_ids) == 2 and not is_pretokenized:
|
|
ids, pair_ids = ids_or_pair_ids
|
|
else:
|
|
ids, pair_ids = ids_or_pair_ids, None
|
|
|
|
first_ids = get_input_ids(ids)
|
|
second_ids = get_input_ids(pair_ids) if pair_ids is not None else None
|
|
input_ids.append((first_ids, second_ids))
|
|
|
|
if max_length is None and pad_to_max_length:
|
|
|
|
def total_sequence_length(input_pairs):
|
|
first_ids, second_ids = input_pairs
|
|
return len(first_ids) + (
|
|
self.num_special_tokens_to_add()
|
|
if second_ids is None
|
|
else (len(second_ids) + self.num_special_tokens_to_add(pair=True))
|
|
)
|
|
|
|
max_length = max([total_sequence_length(ids) for ids in input_ids])
|
|
|
|
batch_outputs = {}
|
|
for first_ids, second_ids in input_ids:
|
|
# Prepares a sequence of input id, or a pair of sequences of inputs ids so that it can be used by
|
|
# the model. It adds special tokens, truncates sequences if overflowing while taking into account
|
|
# the special tokens and manages a window stride for overflowing tokens
|
|
outputs = self.prepare_for_model(
|
|
first_ids,
|
|
pair_ids=second_ids,
|
|
max_length=max_length,
|
|
pad_to_max_length=pad_to_max_length,
|
|
add_special_tokens=add_special_tokens,
|
|
stride=stride,
|
|
truncation_strategy=truncation_strategy,
|
|
return_attention_mask=return_attention_masks,
|
|
return_token_type_ids=return_token_type_ids,
|
|
return_overflowing_tokens=return_overflowing_tokens,
|
|
return_special_tokens_mask=return_special_tokens_masks,
|
|
)
|
|
|
|
# Append the non-padded length to the output
|
|
if return_input_lengths:
|
|
outputs["input_len"] = len(outputs["input_ids"])
|
|
|
|
for key, value in outputs.items():
|
|
if key not in batch_outputs:
|
|
batch_outputs[key] = []
|
|
batch_outputs[key].append(value)
|
|
|
|
if return_tensors is not None:
|
|
|
|
# Do the tensor conversion in batch
|
|
for key, value in batch_outputs.items():
|
|
if return_tensors == "tf" and is_tf_available():
|
|
try:
|
|
batch_outputs[key] = tf.constant(value)
|
|
except ValueError:
|
|
if None in [item for sequence in value for item in sequence]:
|
|
raise ValueError(self.NO_PAD_TOKEN_FOR_BATCH_MSG)
|
|
else:
|
|
raise ValueError(self.UNEVEN_SEQUENCES_FOR_BATCH_MSG)
|
|
elif return_tensors == "pt" and is_torch_available():
|
|
try:
|
|
batch_outputs[key] = torch.tensor(value)
|
|
except ValueError:
|
|
raise ValueError(self.UNEVEN_SEQUENCES_FOR_BATCH_MSG)
|
|
except RuntimeError:
|
|
if None in [item for sequence in value for item in sequence]:
|
|
raise ValueError(self.NO_PAD_TOKEN_FOR_BATCH_MSG)
|
|
else:
|
|
raise
|
|
elif return_tensors is not None:
|
|
logger.warning(
|
|
"Unable to convert output to tensors format {}, PyTorch or TensorFlow is not available.".format(
|
|
return_tensors
|
|
)
|
|
)
|
|
|
|
return BatchEncoding(batch_outputs)
|
|
|
|
def prepare_for_model(
|
|
self,
|
|
ids: List[int],
|
|
pair_ids: Optional[List[int]] = None,
|
|
max_length: Optional[int] = None,
|
|
add_special_tokens: bool = True,
|
|
stride: int = 0,
|
|
truncation_strategy: str = "longest_first",
|
|
pad_to_max_length: bool = False,
|
|
return_tensors: Optional[str] = None,
|
|
return_token_type_ids: Optional[bool] = None,
|
|
return_attention_mask: Optional[bool] = None,
|
|
return_overflowing_tokens: bool = False,
|
|
return_special_tokens_mask: bool = False,
|
|
):
|
|
"""
|
|
Prepares a sequence of input id, or a pair of sequences of inputs ids so that it can be used by the model.
|
|
It adds special tokens, truncates
|
|
sequences if overflowing while taking into account the special tokens and manages a window stride for
|
|
overflowing tokens
|
|
|
|
Args:
|
|
ids: list of tokenized input ids. Can be obtained from a string by chaining the
|
|
`tokenize` and `convert_tokens_to_ids` methods.
|
|
pair_ids: Optional second list of input ids. Can be obtained from a string by chaining the
|
|
`tokenize` and `convert_tokens_to_ids` methods.
|
|
max_length: maximum length of the returned list. Will truncate by taking into account the special tokens.
|
|
add_special_tokens: if set to ``True``, the sequences will be encoded with the special tokens relative
|
|
to their model.
|
|
stride: window stride for overflowing tokens. Can be useful for edge effect removal when using sequential
|
|
list of inputs.
|
|
truncation_strategy: string selected in the following options:
|
|
- 'longest_first' (default) Iteratively reduce the inputs sequence until the input is under max_length
|
|
starting from the longest one at each token (when there is a pair of input sequences)
|
|
- 'only_first': Only truncate the first sequence
|
|
- 'only_second': Only truncate the second sequence
|
|
- 'do_not_truncate': Does not truncate (raise an error if the input sequence is longer than max_length)
|
|
pad_to_max_length: if set to True, the returned sequences will be padded according to the model's padding side and
|
|
padding index, up to their max length. If no max length is specified, the padding is done up to the model's max length.
|
|
The tokenizer padding sides are handled by the following strings:
|
|
- 'left': pads on the left of the sequences
|
|
- 'right': pads on the right of the sequences
|
|
Defaults to False: no padding.
|
|
return_tensors: (optional) can be set to 'tf' or 'pt' to return respectively TensorFlow tf.constant
|
|
or PyTorch torch.Tensor instead of a list of python integers.
|
|
return_token_type_ids: (optional) Set to False to avoid returning token_type_ids (default True).
|
|
return_attention_mask: (optional) Set to False to avoid returning attention mask (default True)
|
|
return_overflowing_tokens: (optional) Set to True to return overflowing token information (default False).
|
|
return_special_tokens_mask: (optional) Set to True to return special tokens mask information (default False).
|
|
|
|
Return:
|
|
A Dictionary of shape::
|
|
|
|
{
|
|
input_ids: list[int],
|
|
token_type_ids: list[int] if return_token_type_ids is True (default)
|
|
overflowing_tokens: list[int] if a ``max_length`` is specified and return_overflowing_tokens is True
|
|
num_truncated_tokens: int if a ``max_length`` is specified and return_overflowing_tokens is True
|
|
special_tokens_mask: list[int] if ``add_special_tokens`` if set to ``True`` and return_special_tokens_mask is True
|
|
}
|
|
|
|
With the fields:
|
|
``input_ids``: list of token ids to be fed to a model
|
|
``token_type_ids``: list of token type ids to be fed to a model
|
|
|
|
``overflowing_tokens``: list of overflowing tokens if a max length is specified.
|
|
``num_truncated_tokens``: number of overflowing tokens a ``max_length`` is specified
|
|
``special_tokens_mask``: if adding special tokens, this is a list of [0, 1], with 0 specifying special added
|
|
tokens and 1 specifying sequence tokens.
|
|
"""
|
|
pair = bool(pair_ids is not None)
|
|
len_ids = len(ids)
|
|
len_pair_ids = len(pair_ids) if pair else 0
|
|
|
|
if return_token_type_ids is None:
|
|
return_token_type_ids = "token_type_ids" in self.model_input_names
|
|
if return_attention_mask is None:
|
|
return_attention_mask = "attention_mask" in self.model_input_names
|
|
|
|
encoded_inputs = {}
|
|
|
|
# Handle max sequence length
|
|
total_len = len_ids + len_pair_ids + (self.num_special_tokens_to_add(pair=pair) if add_special_tokens else 0)
|
|
if max_length and total_len > max_length:
|
|
ids, pair_ids, overflowing_tokens = self.truncate_sequences(
|
|
ids,
|
|
pair_ids=pair_ids,
|
|
num_tokens_to_remove=total_len - max_length,
|
|
truncation_strategy=truncation_strategy,
|
|
stride=stride,
|
|
)
|
|
if return_overflowing_tokens:
|
|
encoded_inputs["overflowing_tokens"] = overflowing_tokens
|
|
encoded_inputs["num_truncated_tokens"] = total_len - max_length
|
|
|
|
# Handle special_tokens
|
|
if add_special_tokens:
|
|
sequence = self.build_inputs_with_special_tokens(ids, pair_ids)
|
|
token_type_ids = self.create_token_type_ids_from_sequences(ids, pair_ids)
|
|
else:
|
|
sequence = ids + pair_ids if pair else ids
|
|
token_type_ids = [0] * len(ids) + ([1] * len(pair_ids) if pair else [])
|
|
|
|
if return_special_tokens_mask:
|
|
if add_special_tokens:
|
|
encoded_inputs["special_tokens_mask"] = self.get_special_tokens_mask(ids, pair_ids)
|
|
else:
|
|
encoded_inputs["special_tokens_mask"] = [0] * len(sequence)
|
|
|
|
encoded_inputs["input_ids"] = sequence
|
|
if return_token_type_ids:
|
|
encoded_inputs["token_type_ids"] = token_type_ids
|
|
|
|
if max_length and len(encoded_inputs["input_ids"]) > max_length:
|
|
encoded_inputs["input_ids"] = encoded_inputs["input_ids"][:max_length]
|
|
if return_token_type_ids:
|
|
encoded_inputs["token_type_ids"] = encoded_inputs["token_type_ids"][:max_length]
|
|
if return_special_tokens_mask:
|
|
encoded_inputs["special_tokens_mask"] = encoded_inputs["special_tokens_mask"][:max_length]
|
|
|
|
if max_length is None and len(encoded_inputs["input_ids"]) > self.max_len:
|
|
logger.warning(
|
|
"Token indices sequence length is longer than the specified maximum sequence length "
|
|
"for this model ({} > {}). Running this sequence through the model will result in "
|
|
"indexing errors".format(len(ids), self.max_len)
|
|
)
|
|
|
|
needs_to_be_padded = pad_to_max_length and (
|
|
max_length
|
|
and len(encoded_inputs["input_ids"]) < max_length
|
|
or max_length is None
|
|
and len(encoded_inputs["input_ids"]) < self.max_len
|
|
and self.max_len <= 10000
|
|
)
|
|
|
|
if pad_to_max_length and max_length is None and self.max_len > 10000:
|
|
logger.warning(
|
|
"Sequence can't be padded as no maximum length is specified and the model maximum length is too high."
|
|
)
|
|
|
|
if needs_to_be_padded:
|
|
difference = (max_length if max_length is not None else self.max_len) - len(encoded_inputs["input_ids"])
|
|
|
|
if self.padding_side == "right":
|
|
if return_attention_mask:
|
|
encoded_inputs["attention_mask"] = [1] * len(encoded_inputs["input_ids"]) + [0] * difference
|
|
if return_token_type_ids:
|
|
encoded_inputs["token_type_ids"] = (
|
|
encoded_inputs["token_type_ids"] + [self.pad_token_type_id] * difference
|
|
)
|
|
if return_special_tokens_mask:
|
|
encoded_inputs["special_tokens_mask"] = encoded_inputs["special_tokens_mask"] + [1] * difference
|
|
encoded_inputs["input_ids"] = encoded_inputs["input_ids"] + [self.pad_token_id] * difference
|
|
elif self.padding_side == "left":
|
|
if return_attention_mask:
|
|
encoded_inputs["attention_mask"] = [0] * difference + [1] * len(encoded_inputs["input_ids"])
|
|
if return_token_type_ids:
|
|
encoded_inputs["token_type_ids"] = [self.pad_token_type_id] * difference + encoded_inputs[
|
|
"token_type_ids"
|
|
]
|
|
if return_special_tokens_mask:
|
|
encoded_inputs["special_tokens_mask"] = [1] * difference + encoded_inputs["special_tokens_mask"]
|
|
encoded_inputs["input_ids"] = [self.pad_token_id] * difference + encoded_inputs["input_ids"]
|
|
|
|
else:
|
|
raise ValueError("Invalid padding strategy:" + str(self.padding_side))
|
|
|
|
elif return_attention_mask:
|
|
encoded_inputs["attention_mask"] = [1] * len(encoded_inputs["input_ids"])
|
|
|
|
# Prepare inputs as tensors if asked
|
|
if return_tensors == "tf" and is_tf_available():
|
|
encoded_inputs["input_ids"] = tf.constant([encoded_inputs["input_ids"]])
|
|
|
|
if "token_type_ids" in encoded_inputs:
|
|
encoded_inputs["token_type_ids"] = tf.constant([encoded_inputs["token_type_ids"]])
|
|
|
|
if "attention_mask" in encoded_inputs:
|
|
encoded_inputs["attention_mask"] = tf.constant([encoded_inputs["attention_mask"]])
|
|
|
|
elif return_tensors == "pt" and is_torch_available():
|
|
encoded_inputs["input_ids"] = torch.tensor([encoded_inputs["input_ids"]])
|
|
|
|
if "token_type_ids" in encoded_inputs:
|
|
encoded_inputs["token_type_ids"] = torch.tensor([encoded_inputs["token_type_ids"]])
|
|
|
|
if "attention_mask" in encoded_inputs:
|
|
encoded_inputs["attention_mask"] = torch.tensor([encoded_inputs["attention_mask"]])
|
|
elif return_tensors is not None:
|
|
logger.warning(
|
|
"Unable to convert output to tensors format {}, PyTorch or TensorFlow is not available.".format(
|
|
return_tensors
|
|
)
|
|
)
|
|
|
|
return BatchEncoding(encoded_inputs)
|
|
|
|
def prepare_for_tokenization(self, text, **kwargs):
|
|
""" Performs any necessary transformations before tokenization """
|
|
return text
|
|
|
|
def truncate_sequences(
|
|
self, ids, pair_ids=None, num_tokens_to_remove=0, truncation_strategy="longest_first", stride=0
|
|
):
|
|
"""Truncates a sequence pair in place to the maximum length.
|
|
truncation_strategy: string selected in the following options:
|
|
- 'longest_first' (default) Iteratively reduce the inputs sequence until the input is under max_length
|
|
starting from the longest one at each token (when there is a pair of input sequences).
|
|
Overflowing tokens only contains overflow from the first sequence.
|
|
- 'only_first': Only truncate the first sequence. raise an error if the first sequence is shorter or equal to than num_tokens_to_remove.
|
|
- 'only_second': Only truncate the second sequence
|
|
- 'do_not_truncate': Does not truncate (raise an error if the input sequence is longer than max_length)
|
|
"""
|
|
if num_tokens_to_remove <= 0:
|
|
return ids, pair_ids, []
|
|
|
|
if truncation_strategy == "longest_first":
|
|
overflowing_tokens = []
|
|
for _ in range(num_tokens_to_remove):
|
|
if pair_ids is None or len(ids) > len(pair_ids):
|
|
overflowing_tokens = [ids[-1]] + overflowing_tokens
|
|
ids = ids[:-1]
|
|
else:
|
|
pair_ids = pair_ids[:-1]
|
|
window_len = min(len(ids), stride)
|
|
if window_len > 0:
|
|
overflowing_tokens = ids[-window_len:] + overflowing_tokens
|
|
elif truncation_strategy == "only_first":
|
|
assert len(ids) > num_tokens_to_remove
|
|
window_len = min(len(ids), stride + num_tokens_to_remove)
|
|
overflowing_tokens = ids[-window_len:]
|
|
ids = ids[:-num_tokens_to_remove]
|
|
elif truncation_strategy == "only_second":
|
|
assert pair_ids is not None and len(pair_ids) > num_tokens_to_remove
|
|
window_len = min(len(pair_ids), stride + num_tokens_to_remove)
|
|
overflowing_tokens = pair_ids[-window_len:]
|
|
pair_ids = pair_ids[:-num_tokens_to_remove]
|
|
elif truncation_strategy == "do_not_truncate":
|
|
raise ValueError("Input sequence are too long for max_length. Please select a truncation strategy.")
|
|
else:
|
|
raise ValueError(
|
|
"Truncation_strategy should be selected in ['longest_first', 'only_first', 'only_second', 'do_not_truncate']"
|
|
)
|
|
return (ids, pair_ids, overflowing_tokens)
|
|
|
|
def create_token_type_ids_from_sequences(self, token_ids_0, token_ids_1=None):
|
|
if token_ids_1 is None:
|
|
return len(token_ids_0) * [0]
|
|
return [0] * len(token_ids_0) + [1] * len(token_ids_1)
|
|
|
|
def build_inputs_with_special_tokens(self, token_ids_0, token_ids_1=None):
|
|
"""
|
|
Build model inputs from a sequence or a pair of sequence for sequence classification tasks
|
|
by concatenating and adding special tokens.
|
|
A RoBERTa sequence has the following format:
|
|
single sequence: <s> X </s>
|
|
pair of sequences: <s> A </s></s> B </s>
|
|
"""
|
|
if token_ids_1 is None:
|
|
return token_ids_0
|
|
return token_ids_0 + token_ids_1
|
|
|
|
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 ``prepare_for_model`` or ``encode_plus`` methods.
|
|
|
|
Args:
|
|
token_ids_0: list of ids (must not contain special tokens)
|
|
token_ids_1: Optional list of ids (must not contain special tokens), necessary when fetching sequence ids
|
|
for sequence pairs
|
|
already_has_special_tokens: (default False) Set to True if the token list is already formated with
|
|
special tokens for the model
|
|
|
|
Returns:
|
|
A list of integers in the range [0, 1]: 1 for a special token, 0 for a sequence token.
|
|
"""
|
|
return [0] * ((len(token_ids_1) if token_ids_1 else 0) + len(token_ids_0))
|
|
|
|
def convert_ids_to_tokens(self, ids, skip_special_tokens=False):
|
|
""" Converts a single index or a sequence of indices (integers) in a token "
|
|
(resp.) a sequence of tokens (str), using the vocabulary and added tokens.
|
|
|
|
Args:
|
|
skip_special_tokens: Don't decode special tokens (self.all_special_tokens). Default: False
|
|
"""
|
|
if isinstance(ids, int):
|
|
if ids in self.added_tokens_decoder:
|
|
return self.added_tokens_decoder[ids]
|
|
else:
|
|
return self._convert_id_to_token(ids)
|
|
tokens = []
|
|
for index in ids:
|
|
index = int(index)
|
|
if skip_special_tokens and index in self.all_special_ids:
|
|
continue
|
|
if index in self.added_tokens_decoder:
|
|
tokens.append(self.added_tokens_decoder[index])
|
|
else:
|
|
tokens.append(self._convert_id_to_token(index))
|
|
return tokens
|
|
|
|
def _convert_id_to_token(self, index):
|
|
raise NotImplementedError
|
|
|
|
def convert_tokens_to_string(self, tokens):
|
|
""" Converts a sequence of tokens (string) in a single string.
|
|
The most simple way to do it is ' '.join(self.convert_ids_to_tokens(token_ids))
|
|
but we often want to remove sub-word tokenization artifacts at the same time.
|
|
"""
|
|
return " ".join(self.convert_ids_to_tokens(tokens))
|
|
|
|
def decode(self, token_ids, skip_special_tokens=False, clean_up_tokenization_spaces=True):
|
|
"""
|
|
Converts a sequence of ids (integer) in a string, using the tokenizer and vocabulary
|
|
with options to remove special tokens and clean up tokenization spaces.
|
|
Similar to doing ``self.convert_tokens_to_string(self.convert_ids_to_tokens(token_ids))``.
|
|
|
|
Args:
|
|
token_ids: list of tokenized input ids. Can be obtained using the `encode` or `encode_plus` methods.
|
|
skip_special_tokens: if set to True, will replace special tokens.
|
|
clean_up_tokenization_spaces: if set to True, will clean up the tokenization spaces.
|
|
"""
|
|
filtered_tokens = self.convert_ids_to_tokens(token_ids, skip_special_tokens=skip_special_tokens)
|
|
|
|
# To avoid mixing byte-level and unicode for byte-level BPT
|
|
# we need to build string separatly for added tokens and byte-level tokens
|
|
# cf. https://github.com/huggingface/transformers/issues/1133
|
|
sub_texts = []
|
|
current_sub_text = []
|
|
for token in filtered_tokens:
|
|
if skip_special_tokens and token in self.all_special_ids:
|
|
continue
|
|
if token in self.added_tokens_encoder:
|
|
if current_sub_text:
|
|
sub_texts.append(self.convert_tokens_to_string(current_sub_text))
|
|
current_sub_text = []
|
|
sub_texts.append(token)
|
|
else:
|
|
current_sub_text.append(token)
|
|
if current_sub_text:
|
|
sub_texts.append(self.convert_tokens_to_string(current_sub_text))
|
|
text = " ".join(sub_texts)
|
|
|
|
if clean_up_tokenization_spaces:
|
|
clean_text = self.clean_up_tokenization(text)
|
|
return clean_text
|
|
else:
|
|
return text
|
|
|
|
@staticmethod
|
|
def clean_up_tokenization(out_string):
|
|
""" Clean up a list of simple English tokenization artifacts like spaces before punctuations and abreviated forms.
|
|
"""
|
|
out_string = (
|
|
out_string.replace(" .", ".")
|
|
.replace(" ?", "?")
|
|
.replace(" !", "!")
|
|
.replace(" ,", ",")
|
|
.replace(" ' ", "'")
|
|
.replace(" n't", "n't")
|
|
.replace(" 'm", "'m")
|
|
.replace(" do not", " don't")
|
|
.replace(" 's", "'s")
|
|
.replace(" 've", "'ve")
|
|
.replace(" 're", "'re")
|
|
)
|
|
return out_string
|
|
|
|
|
|
def trim_batch(
|
|
input_ids, pad_token_id, attention_mask=None,
|
|
):
|
|
"""Remove columns that are populated exclusively by pad_token_id"""
|
|
keep_column_mask = input_ids.ne(pad_token_id).any(dim=0)
|
|
if attention_mask is None:
|
|
return input_ids[:, keep_column_mask]
|
|
else:
|
|
return (input_ids[:, keep_column_mask], attention_mask[:, keep_column_mask])
|
|
|
|
|
|
|
|
def load_vocab(vocab_file):
|
|
"""Loads a vocabulary file into a dictionary."""
|
|
vocab = collections.OrderedDict()
|
|
with open(vocab_file, "r", encoding="utf-8") as reader:
|
|
tokens = reader.readlines()
|
|
for index, token in enumerate(tokens):
|
|
token = token.rstrip("\n")
|
|
vocab[token] = index
|
|
return vocab
|
|
|
|
|
|
def whitespace_tokenize(text):
|
|
"""Runs basic whitespace cleaning and splitting on a piece of text."""
|
|
text = text.strip()
|
|
if not text:
|
|
return []
|
|
tokens = text.split()
|
|
return tokens
|
|
|
|
|
|
VOCAB_FILES_NAMES = {"vocab_file": "vocab.txt"}
|
|
|
|
PRETRAINED_VOCAB_FILES_MAP = {
|
|
"vocab_file": {
|
|
"bert-base-uncased": "https://s3.amazonaws.com/models.huggingface.co/bert/bert-base-uncased-vocab.txt",
|
|
"bert-large-uncased": "https://s3.amazonaws.com/models.huggingface.co/bert/bert-large-uncased-vocab.txt",
|
|
"bert-base-cased": "https://s3.amazonaws.com/models.huggingface.co/bert/bert-base-cased-vocab.txt",
|
|
"bert-large-cased": "https://s3.amazonaws.com/models.huggingface.co/bert/bert-large-cased-vocab.txt",
|
|
"bert-base-multilingual-uncased": "https://s3.amazonaws.com/models.huggingface.co/bert/bert-base-multilingual-uncased-vocab.txt",
|
|
"bert-base-multilingual-cased": "https://s3.amazonaws.com/models.huggingface.co/bert/bert-base-multilingual-cased-vocab.txt",
|
|
"bert-base-chinese": "https://s3.amazonaws.com/models.huggingface.co/bert/bert-base-chinese-vocab.txt",
|
|
"bert-base-german-cased": "https://int-deepset-models-bert.s3.eu-central-1.amazonaws.com/pytorch/bert-base-german-cased-vocab.txt",
|
|
"bert-large-uncased-whole-word-masking": "https://s3.amazonaws.com/models.huggingface.co/bert/bert-large-uncased-whole-word-masking-vocab.txt",
|
|
"bert-large-cased-whole-word-masking": "https://s3.amazonaws.com/models.huggingface.co/bert/bert-large-cased-whole-word-masking-vocab.txt",
|
|
"bert-large-uncased-whole-word-masking-finetuned-squad": "https://s3.amazonaws.com/models.huggingface.co/bert/bert-large-uncased-whole-word-masking-finetuned-squad-vocab.txt",
|
|
"bert-large-cased-whole-word-masking-finetuned-squad": "https://s3.amazonaws.com/models.huggingface.co/bert/bert-large-cased-whole-word-masking-finetuned-squad-vocab.txt",
|
|
"bert-base-cased-finetuned-mrpc": "https://s3.amazonaws.com/models.huggingface.co/bert/bert-base-cased-finetuned-mrpc-vocab.txt",
|
|
"bert-base-german-dbmdz-cased": "https://s3.amazonaws.com/models.huggingface.co/bert/bert-base-german-dbmdz-cased-vocab.txt",
|
|
"bert-base-german-dbmdz-uncased": "https://s3.amazonaws.com/models.huggingface.co/bert/bert-base-german-dbmdz-uncased-vocab.txt",
|
|
"bert-base-finnish-cased-v1": "https://s3.amazonaws.com/models.huggingface.co/bert/TurkuNLP/bert-base-finnish-cased-v1/vocab.txt",
|
|
"bert-base-finnish-uncased-v1": "https://s3.amazonaws.com/models.huggingface.co/bert/TurkuNLP/bert-base-finnish-uncased-v1/vocab.txt",
|
|
"bert-base-dutch-cased": "https://s3.amazonaws.com/models.huggingface.co/bert/wietsedv/bert-base-dutch-cased/vocab.txt",
|
|
}
|
|
}
|
|
|
|
PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES = {
|
|
"bert-base-uncased": 512,
|
|
"bert-large-uncased": 512,
|
|
"bert-base-cased": 512,
|
|
"bert-large-cased": 512,
|
|
"bert-base-multilingual-uncased": 512,
|
|
"bert-base-multilingual-cased": 512,
|
|
"bert-base-chinese": 512,
|
|
"bert-base-german-cased": 512,
|
|
"bert-large-uncased-whole-word-masking": 512,
|
|
"bert-large-cased-whole-word-masking": 512,
|
|
"bert-large-uncased-whole-word-masking-finetuned-squad": 512,
|
|
"bert-large-cased-whole-word-masking-finetuned-squad": 512,
|
|
"bert-base-cased-finetuned-mrpc": 512,
|
|
"bert-base-german-dbmdz-cased": 512,
|
|
"bert-base-german-dbmdz-uncased": 512,
|
|
"bert-base-finnish-cased-v1": 512,
|
|
"bert-base-finnish-uncased-v1": 512,
|
|
"bert-base-dutch-cased": 512,
|
|
}
|
|
|
|
PRETRAINED_INIT_CONFIGURATION = {
|
|
"bert-base-uncased": {"do_lower_case": True},
|
|
"bert-large-uncased": {"do_lower_case": True},
|
|
"bert-base-cased": {"do_lower_case": False},
|
|
"bert-large-cased": {"do_lower_case": False},
|
|
"bert-base-multilingual-uncased": {"do_lower_case": True},
|
|
"bert-base-multilingual-cased": {"do_lower_case": False},
|
|
"bert-base-chinese": {"do_lower_case": False},
|
|
"bert-base-german-cased": {"do_lower_case": False},
|
|
"bert-large-uncased-whole-word-masking": {"do_lower_case": True},
|
|
"bert-large-cased-whole-word-masking": {"do_lower_case": False},
|
|
"bert-large-uncased-whole-word-masking-finetuned-squad": {"do_lower_case": True},
|
|
"bert-large-cased-whole-word-masking-finetuned-squad": {"do_lower_case": False},
|
|
"bert-base-cased-finetuned-mrpc": {"do_lower_case": False},
|
|
"bert-base-german-dbmdz-cased": {"do_lower_case": False},
|
|
"bert-base-german-dbmdz-uncased": {"do_lower_case": True},
|
|
"bert-base-finnish-cased-v1": {"do_lower_case": False},
|
|
"bert-base-finnish-uncased-v1": {"do_lower_case": True},
|
|
"bert-base-dutch-cased": {"do_lower_case": False},
|
|
}
|
|
|
|
|
|
# Bert Classes
|
|
class BertTokenizer(PreTrainedTokenizer):
|
|
r"""
|
|
Constructs a BERT tokenizer. Based on WordPiece.
|
|
|
|
This tokenizer inherits from :class:`~transformers.PreTrainedTokenizer` which contains most of the methods. Users
|
|
should refer to the superclass for more information regarding methods.
|
|
|
|
Args:
|
|
vocab_file (:obj:`string`):
|
|
File containing the vocabulary.
|
|
do_lower_case (:obj:`bool`, `optional`, defaults to :obj:`True`):
|
|
Whether to lowercase the input when tokenizing.
|
|
do_basic_tokenize (:obj:`bool`, `optional`, defaults to :obj:`True`):
|
|
Whether to do basic tokenization before WordPiece.
|
|
never_split (:obj:`bool`, `optional`, defaults to :obj:`True`):
|
|
List of tokens which will never be split during tokenization. Only has an effect when
|
|
:obj:`do_basic_tokenize=True`
|
|
unk_token (:obj:`string`, `optional`, defaults to "[UNK]"):
|
|
The unknown token. A token that is not in the vocabulary cannot be converted to an ID and is set to be this
|
|
token instead.
|
|
sep_token (:obj:`string`, `optional`, defaults to "[SEP]"):
|
|
The separator token, which is used when building a sequence from multiple sequences, e.g. two sequences
|
|
for sequence classification or for a text and a question for question answering.
|
|
It is also used as the last token of a sequence built with special tokens.
|
|
pad_token (:obj:`string`, `optional`, defaults to "[PAD]"):
|
|
The token used for padding, for example when batching sequences of different lengths.
|
|
cls_token (:obj:`string`, `optional`, defaults to "[CLS]"):
|
|
The classifier token which is used when doing sequence classification (classification of the whole
|
|
sequence instead of per-token classification). It is the first token of the sequence when built with
|
|
special tokens.
|
|
mask_token (:obj:`string`, `optional`, defaults to "[MASK]"):
|
|
The token used for masking values. This is the token used when training this model with masked language
|
|
modeling. This is the token which the model will try to predict.
|
|
tokenize_chinese_chars (:obj:`bool`, `optional`, defaults to :obj:`True`):
|
|
Whether to tokenize Chinese characters.
|
|
This should likely be deactivated for Japanese:
|
|
see: https://github.com/huggingface/transformers/issues/328
|
|
"""
|
|
|
|
vocab_files_names = VOCAB_FILES_NAMES
|
|
pretrained_vocab_files_map = PRETRAINED_VOCAB_FILES_MAP
|
|
pretrained_init_configuration = PRETRAINED_INIT_CONFIGURATION
|
|
max_model_input_sizes = PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES
|
|
|
|
def __init__(
|
|
self,
|
|
vocab_file,
|
|
do_lower_case=True,
|
|
do_basic_tokenize=True,
|
|
never_split=None,
|
|
unk_token="[UNK]",
|
|
sep_token="[SEP]",
|
|
pad_token="[PAD]",
|
|
cls_token="[CLS]",
|
|
mask_token="[MASK]",
|
|
tokenize_chinese_chars=True,
|
|
**kwargs
|
|
):
|
|
super().__init__(
|
|
unk_token=unk_token,
|
|
sep_token=sep_token,
|
|
pad_token=pad_token,
|
|
cls_token=cls_token,
|
|
mask_token=mask_token,
|
|
**kwargs,
|
|
)
|
|
self.max_len_single_sentence = self.max_len - 2 # take into account special tokens
|
|
self.max_len_sentences_pair = self.max_len - 3 # take into account special tokens
|
|
|
|
if not os.path.isfile(vocab_file):
|
|
raise ValueError(
|
|
"Can't find a vocabulary file at path '{}'. To load the vocabulary from a Google pretrained "
|
|
"model use `tokenizer = BertTokenizer.from_pretrained(PRETRAINED_MODEL_NAME)`".format(vocab_file)
|
|
)
|
|
self.vocab = load_vocab(vocab_file)
|
|
self.ids_to_tokens = collections.OrderedDict([(ids, tok) for tok, ids in self.vocab.items()])
|
|
self.do_basic_tokenize = do_basic_tokenize
|
|
if do_basic_tokenize:
|
|
self.basic_tokenizer = BasicTokenizer(
|
|
do_lower_case=do_lower_case, never_split=never_split, tokenize_chinese_chars=tokenize_chinese_chars
|
|
)
|
|
self.wordpiece_tokenizer = WordpieceTokenizer(vocab=self.vocab, unk_token=self.unk_token)
|
|
|
|
@property
|
|
def vocab_size(self):
|
|
return len(self.vocab)
|
|
|
|
def get_vocab(self):
|
|
return dict(self.vocab, **self.added_tokens_encoder)
|
|
|
|
def _tokenize(self, text):
|
|
split_tokens = []
|
|
if self.do_basic_tokenize:
|
|
for token in self.basic_tokenizer.tokenize(text, never_split=self.all_special_tokens):
|
|
for sub_token in self.wordpiece_tokenizer.tokenize(token):
|
|
split_tokens.append(sub_token)
|
|
else:
|
|
split_tokens = self.wordpiece_tokenizer.tokenize(text)
|
|
return split_tokens
|
|
|
|
def _convert_token_to_id(self, token):
|
|
""" Converts a token (str) in an id using the vocab. """
|
|
return self.vocab.get(token, self.vocab.get(self.unk_token))
|
|
|
|
def _convert_id_to_token(self, index):
|
|
"""Converts an index (integer) in a token (str) using the vocab."""
|
|
return self.ids_to_tokens.get(index, self.unk_token)
|
|
|
|
def convert_tokens_to_string(self, tokens):
|
|
""" Converts a sequence of tokens (string) in a single string. """
|
|
out_string = " ".join(tokens).replace(" ##", "").strip()
|
|
return out_string
|
|
|
|
def build_inputs_with_special_tokens(
|
|
self, token_ids_0: List[int], token_ids_1: Optional[List[int]] = None
|
|
) -> List[int]:
|
|
"""
|
|
Build model inputs from a sequence or a pair of sequence for sequence classification tasks
|
|
by concatenating and adding special tokens.
|
|
A BERT sequence has the following format:
|
|
|
|
- single sequence: ``[CLS] X [SEP]``
|
|
- pair of sequences: ``[CLS] A [SEP] B [SEP]``
|
|
|
|
Args:
|
|
token_ids_0 (:obj:`List[int]`):
|
|
List of IDs to which the special tokens will be added
|
|
token_ids_1 (:obj:`List[int]`, `optional`, defaults to :obj:`None`):
|
|
Optional second list of IDs for sequence pairs.
|
|
|
|
Returns:
|
|
:obj:`List[int]`: list of `input IDs <../glossary.html#input-ids>`__ with the appropriate special tokens.
|
|
"""
|
|
if token_ids_1 is None:
|
|
return [self.cls_token_id] + token_ids_0 + [self.sep_token_id]
|
|
cls = [self.cls_token_id]
|
|
sep = [self.sep_token_id]
|
|
return cls + token_ids_0 + sep + token_ids_1 + sep
|
|
|
|
def get_special_tokens_mask(
|
|
self, token_ids_0: List[int], token_ids_1: Optional[List[int]] = None, already_has_special_tokens: bool = False
|
|
) -> List[int]:
|
|
"""
|
|
Retrieves sequence ids from a token list that has no special tokens added. This method is called when adding
|
|
special tokens using the tokenizer ``prepare_for_model`` or ``encode_plus`` methods.
|
|
|
|
Args:
|
|
token_ids_0 (:obj:`List[int]`):
|
|
List of ids.
|
|
token_ids_1 (:obj:`List[int]`, `optional`, defaults to :obj:`None`):
|
|
Optional second list of IDs for sequence pairs.
|
|
already_has_special_tokens (:obj:`bool`, `optional`, defaults to :obj:`False`):
|
|
Set to True if the token list is already formatted with special tokens for the model
|
|
|
|
Returns:
|
|
:obj:`List[int]`: A list of integers in the range [0, 1]: 0 for a special token, 1 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 formated 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]
|
|
|
|
def create_token_type_ids_from_sequences(
|
|
self, token_ids_0: List[int], token_ids_1: Optional[List[int]] = None
|
|
) -> List[int]:
|
|
"""
|
|
Creates a mask from the two sequences passed to be used in a sequence-pair classification task.
|
|
A BERT 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, only returns the first portion of the mask (0's).
|
|
|
|
Args:
|
|
token_ids_0 (:obj:`List[int]`):
|
|
List of ids.
|
|
token_ids_1 (:obj:`List[int]`, `optional`, defaults to :obj:`None`):
|
|
Optional second list of IDs for sequence pairs.
|
|
|
|
Returns:
|
|
:obj:`List[int]`: List of `token type IDs <../glossary.html#token-type-ids>`_ 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]
|
|
|
|
def save_vocabulary(self, vocab_path):
|
|
"""
|
|
Save the sentencepiece vocabulary (copy original file) and special tokens file to a directory.
|
|
|
|
Args:
|
|
vocab_path (:obj:`str`):
|
|
The directory in which to save the vocabulary.
|
|
|
|
Returns:
|
|
:obj:`Tuple(str)`: Paths to the files saved.
|
|
"""
|
|
index = 0
|
|
if os.path.isdir(vocab_path):
|
|
vocab_file = os.path.join(vocab_path, VOCAB_FILES_NAMES["vocab_file"])
|
|
else:
|
|
vocab_file = vocab_path
|
|
with open(vocab_file, "w", encoding="utf-8") as writer:
|
|
for token, token_index in sorted(self.vocab.items(), key=lambda kv: kv[1]):
|
|
if index != token_index:
|
|
logger.warning(
|
|
"Saving vocabulary to {}: vocabulary indices are not consecutive."
|
|
" Please check that the vocabulary is not corrupted!".format(vocab_file)
|
|
)
|
|
index = token_index
|
|
writer.write(token + "\n")
|
|
index += 1
|
|
return (vocab_file,)
|
|
|
|
|
|
class BasicTokenizer(object):
|
|
"""Runs basic tokenization (punctuation splitting, lower casing, etc.)."""
|
|
|
|
def __init__(self, do_lower_case=True, never_split=None, tokenize_chinese_chars=True):
|
|
""" Constructs a BasicTokenizer.
|
|
|
|
Args:
|
|
**do_lower_case**: Whether to lower case the input.
|
|
**never_split**: (`optional`) list of str
|
|
Kept for backward compatibility purposes.
|
|
Now implemented directly at the base class level (see :func:`PreTrainedTokenizer.tokenize`)
|
|
List of token not to split.
|
|
**tokenize_chinese_chars**: (`optional`) boolean (default True)
|
|
Whether to tokenize Chinese characters.
|
|
This should likely be deactivated for Japanese:
|
|
see: https://github.com/huggingface/pytorch-pretrained-BERT/issues/328
|
|
"""
|
|
if never_split is None:
|
|
never_split = []
|
|
self.do_lower_case = do_lower_case
|
|
self.never_split = never_split
|
|
self.tokenize_chinese_chars = tokenize_chinese_chars
|
|
|
|
def tokenize(self, text, never_split=None):
|
|
""" Basic Tokenization of a piece of text.
|
|
Split on "white spaces" only, for sub-word tokenization, see WordPieceTokenizer.
|
|
|
|
Args:
|
|
**never_split**: (`optional`) list of str
|
|
Kept for backward compatibility purposes.
|
|
Now implemented directly at the base class level (see :func:`PreTrainedTokenizer.tokenize`)
|
|
List of token not to split.
|
|
"""
|
|
never_split = self.never_split + (never_split if never_split is not None else [])
|
|
text = self._clean_text(text)
|
|
# This was added on November 1st, 2018 for the multilingual and Chinese
|
|
# models. This is also applied to the English models now, but it doesn't
|
|
# matter since the English models were not trained on any Chinese data
|
|
# and generally don't have any Chinese data in them (there are Chinese
|
|
# characters in the vocabulary because Wikipedia does have some Chinese
|
|
# words in the English Wikipedia.).
|
|
if self.tokenize_chinese_chars:
|
|
text = self._tokenize_chinese_chars(text)
|
|
orig_tokens = whitespace_tokenize(text)
|
|
split_tokens = []
|
|
for token in orig_tokens:
|
|
if self.do_lower_case and token not in never_split:
|
|
token = token.lower()
|
|
token = self._run_strip_accents(token)
|
|
split_tokens.extend(self._run_split_on_punc(token, never_split))
|
|
|
|
output_tokens = whitespace_tokenize(" ".join(split_tokens))
|
|
return output_tokens
|
|
|
|
def _run_strip_accents(self, text):
|
|
"""Strips accents from a piece of text."""
|
|
text = unicodedata.normalize("NFD", text)
|
|
output = []
|
|
for char in text:
|
|
cat = unicodedata.category(char)
|
|
if cat == "Mn":
|
|
continue
|
|
output.append(char)
|
|
return "".join(output)
|
|
|
|
def _run_split_on_punc(self, text, never_split=None):
|
|
"""Splits punctuation on a piece of text."""
|
|
if never_split is not None and text in never_split:
|
|
return [text]
|
|
chars = list(text)
|
|
i = 0
|
|
start_new_word = True
|
|
output = []
|
|
while i < len(chars):
|
|
char = chars[i]
|
|
if _is_punctuation(char):
|
|
output.append([char])
|
|
start_new_word = True
|
|
else:
|
|
if start_new_word:
|
|
output.append([])
|
|
start_new_word = False
|
|
output[-1].append(char)
|
|
i += 1
|
|
|
|
return ["".join(x) for x in output]
|
|
|
|
def _tokenize_chinese_chars(self, text):
|
|
"""Adds whitespace around any CJK character."""
|
|
output = []
|
|
for char in text:
|
|
cp = ord(char)
|
|
if self._is_chinese_char(cp):
|
|
output.append(" ")
|
|
output.append(char)
|
|
output.append(" ")
|
|
else:
|
|
output.append(char)
|
|
return "".join(output)
|
|
|
|
def _is_chinese_char(self, cp):
|
|
"""Checks whether CP is the codepoint of a CJK character."""
|
|
# This defines a "chinese character" as anything in the CJK Unicode block:
|
|
# https://en.wikipedia.org/wiki/CJK_Unified_Ideographs_(Unicode_block)
|
|
#
|
|
# Note that the CJK Unicode block is NOT all Japanese and Korean characters,
|
|
# despite its name. The modern Korean Hangul alphabet is a different block,
|
|
# as is Japanese Hiragana and Katakana. Those alphabets are used to write
|
|
# space-separated words, so they are not treated specially and handled
|
|
# like the all of the other languages.
|
|
if (
|
|
(cp >= 0x4E00 and cp <= 0x9FFF)
|
|
or (cp >= 0x3400 and cp <= 0x4DBF) #
|
|
or (cp >= 0x20000 and cp <= 0x2A6DF) #
|
|
or (cp >= 0x2A700 and cp <= 0x2B73F) #
|
|
or (cp >= 0x2B740 and cp <= 0x2B81F) #
|
|
or (cp >= 0x2B820 and cp <= 0x2CEAF) #
|
|
or (cp >= 0xF900 and cp <= 0xFAFF)
|
|
or (cp >= 0x2F800 and cp <= 0x2FA1F) #
|
|
): #
|
|
return True
|
|
|
|
return False
|
|
|
|
def _clean_text(self, text):
|
|
"""Performs invalid character removal and whitespace cleanup on text."""
|
|
output = []
|
|
for char in text:
|
|
cp = ord(char)
|
|
if cp == 0 or cp == 0xFFFD or _is_control(char):
|
|
continue
|
|
if _is_whitespace(char):
|
|
output.append(" ")
|
|
else:
|
|
output.append(char)
|
|
return "".join(output)
|
|
|
|
|
|
class WordpieceTokenizer(object):
|
|
"""Runs WordPiece tokenization."""
|
|
|
|
def __init__(self, vocab, unk_token, max_input_chars_per_word=100):
|
|
self.vocab = vocab
|
|
self.unk_token = unk_token
|
|
self.max_input_chars_per_word = max_input_chars_per_word
|
|
|
|
def tokenize(self, text):
|
|
"""Tokenizes a piece of text into its word pieces.
|
|
|
|
This uses a greedy longest-match-first algorithm to perform tokenization
|
|
using the given vocabulary.
|
|
|
|
For example:
|
|
input = "unaffable"
|
|
output = ["un", "##aff", "##able"]
|
|
|
|
Args:
|
|
text: A single token or whitespace separated tokens. This should have
|
|
already been passed through `BasicTokenizer`.
|
|
|
|
Returns:
|
|
A list of wordpiece tokens.
|
|
"""
|
|
|
|
output_tokens = []
|
|
for token in whitespace_tokenize(text):
|
|
chars = list(token)
|
|
if len(chars) > self.max_input_chars_per_word:
|
|
output_tokens.append(self.unk_token)
|
|
continue
|
|
|
|
is_bad = False
|
|
start = 0
|
|
sub_tokens = []
|
|
while start < len(chars):
|
|
end = len(chars)
|
|
cur_substr = None
|
|
while start < end:
|
|
substr = "".join(chars[start:end])
|
|
if start > 0:
|
|
substr = "##" + substr
|
|
if substr in self.vocab:
|
|
cur_substr = substr
|
|
break
|
|
end -= 1
|
|
if cur_substr is None:
|
|
is_bad = True
|
|
break
|
|
sub_tokens.append(cur_substr)
|
|
start = end
|
|
|
|
if is_bad:
|
|
output_tokens.append(self.unk_token)
|
|
else:
|
|
output_tokens.extend(sub_tokens)
|
|
return output_tokens
|
|
|
|
|
|
def _is_whitespace(char):
|
|
"""Checks whether `chars` is a whitespace character."""
|
|
# \t, \n, and \r are technically contorl characters but we treat them
|
|
# as whitespace since they are generally considered as such.
|
|
if char == " " or char == "\t" or char == "\n" or char == "\r":
|
|
return True
|
|
cat = unicodedata.category(char)
|
|
if cat == "Zs":
|
|
return True
|
|
return False
|
|
|
|
|
|
def _is_control(char):
|
|
"""Checks whether `chars` is a control character."""
|
|
# These are technically control characters but we count them as whitespace
|
|
# characters.
|
|
if char == "\t" or char == "\n" or char == "\r":
|
|
return False
|
|
cat = unicodedata.category(char)
|
|
if cat.startswith("C"):
|
|
return True
|
|
return False
|
|
|
|
|
|
def _is_punctuation(char):
|
|
"""Checks whether `chars` is a punctuation character."""
|
|
cp = ord(char)
|
|
# We treat all non-letter/number ASCII as punctuation.
|
|
# Characters such as "^", "$", and "`" are not in the Unicode
|
|
# Punctuation class but we treat them as punctuation anyways, for
|
|
# consistency.
|
|
if (cp >= 33 and cp <= 47) or (cp >= 58 and cp <= 64) or (cp >= 91 and cp <= 96) or (cp >= 123 and cp <= 126):
|
|
return True
|
|
cat = unicodedata.category(char)
|
|
if cat.startswith("P"):
|
|
return True
|
|
return False
|