欧卫
'add_app_files'
58627fa
"""
Source: DPR Implementation from Facebook Research
https://github.com/facebookresearch/DPR/tree/master/dpr
"""
import string
import spacy
import regex
import unicodedata
class Tokens(object):
"""A class to represent a list of tokenized text."""
TEXT = 0
TEXT_WS = 1
SPAN = 2
POS = 3
LEMMA = 4
NER = 5
def __init__(self, data, annotators, opts=None):
self.data = data
self.annotators = annotators
self.opts = opts or {}
def __len__(self):
"""The number of tokens."""
return len(self.data)
def slice(self, i=None, j=None):
"""Return a view of the list of tokens from [i, j)."""
new_tokens = copy.copy(self)
new_tokens.data = self.data[i: j]
return new_tokens
def untokenize(self):
"""Returns the original text (with whitespace reinserted)."""
return ''.join([t[self.TEXT_WS] for t in self.data]).strip()
def words(self, uncased=False):
"""Returns a list of the text of each token
Args:
uncased: lower cases text
"""
if uncased:
return [t[self.TEXT].lower() for t in self.data]
else:
return [t[self.TEXT] for t in self.data]
def offsets(self):
"""Returns a list of [start, end) character offsets of each token."""
return [t[self.SPAN] for t in self.data]
def pos(self):
"""Returns a list of part-of-speech tags of each token.
Returns None if this annotation was not included.
"""
if 'pos' not in self.annotators:
return None
return [t[self.POS] for t in self.data]
def lemmas(self):
"""Returns a list of the lemmatized text of each token.
Returns None if this annotation was not included.
"""
if 'lemma' not in self.annotators:
return None
return [t[self.LEMMA] for t in self.data]
def entities(self):
"""Returns a list of named-entity-recognition tags of each token.
Returns None if this annotation was not included.
"""
if 'ner' not in self.annotators:
return None
return [t[self.NER] for t in self.data]
def ngrams(self, n=1, uncased=False, filter_fn=None, as_strings=True):
"""Returns a list of all ngrams from length 1 to n.
Args:
n: upper limit of ngram length
uncased: lower cases text
filter_fn: user function that takes in an ngram list and returns
True or False to keep or not keep the ngram
as_string: return the ngram as a string vs list
"""
def _skip(gram):
if not filter_fn:
return False
return filter_fn(gram)
words = self.words(uncased)
ngrams = [(s, e + 1)
for s in range(len(words))
for e in range(s, min(s + n, len(words)))
if not _skip(words[s:e + 1])]
# Concatenate into strings
if as_strings:
ngrams = ['{}'.format(' '.join(words[s:e])) for (s, e) in ngrams]
return ngrams
def entity_groups(self):
"""Group consecutive entity tokens with the same NER tag."""
entities = self.entities()
if not entities:
return None
non_ent = self.opts.get('non_ent', 'O')
groups = []
idx = 0
while idx < len(entities):
ner_tag = entities[idx]
# Check for entity tag
if ner_tag != non_ent:
# Chomp the sequence
start = idx
while (idx < len(entities) and entities[idx] == ner_tag):
idx += 1
groups.append((self.slice(start, idx).untokenize(), ner_tag))
else:
idx += 1
return groups
class Tokenizer(object):
"""Base tokenizer class.
Tokenizers implement tokenize, which should return a Tokens class.
"""
def tokenize(self, text):
raise NotImplementedError
def shutdown(self):
pass
def __del__(self):
self.shutdown()
class SimpleTokenizer(Tokenizer):
ALPHA_NUM = r'[\p{L}\p{N}\p{M}]+'
NON_WS = r'[^\p{Z}\p{C}]'
def __init__(self, **kwargs):
"""
Args:
annotators: None or empty set (only tokenizes).
"""
self._regexp = regex.compile(
'(%s)|(%s)' % (self.ALPHA_NUM, self.NON_WS),
flags=regex.IGNORECASE + regex.UNICODE + regex.MULTILINE
)
if len(kwargs.get('annotators', {})) > 0:
logger.warning('%s only tokenizes! Skipping annotators: %s' %
(type(self).__name__, kwargs.get('annotators')))
self.annotators = set()
def tokenize(self, text):
data = []
matches = [m for m in self._regexp.finditer(text)]
for i in range(len(matches)):
# Get text
token = matches[i].group()
# Get whitespace
span = matches[i].span()
start_ws = span[0]
if i + 1 < len(matches):
end_ws = matches[i + 1].span()[0]
else:
end_ws = span[1]
# Format data
data.append((
token,
text[start_ws: end_ws],
span,
))
return Tokens(data, self.annotators)
def has_answer(tokenized_answers, text):
text = DPR_normalize(text)
for single_answer in tokenized_answers:
for i in range(0, len(text) - len(single_answer) + 1):
if single_answer == text[i: i + len(single_answer)]:
return True
return False
def locate_answers(tokenized_answers, text):
"""
Returns each occurrence of an answer as (offset, endpos) in terms of *characters*.
"""
tokenized_text = DPR_tokenize(text)
occurrences = []
text_words, text_word_positions = tokenized_text.words(uncased=True), tokenized_text.offsets()
answers_words = [ans.words(uncased=True) for ans in tokenized_answers]
for single_answer in answers_words:
for i in range(0, len(text_words) - len(single_answer) + 1):
if single_answer == text_words[i: i + len(single_answer)]:
(offset, _), (_, endpos) = text_word_positions[i], text_word_positions[i+len(single_answer)-1]
occurrences.append((offset, endpos))
return occurrences
STokenizer = SimpleTokenizer()
def DPR_tokenize(text):
return STokenizer.tokenize(unicodedata.normalize('NFD', text))
def DPR_normalize(text):
return DPR_tokenize(text).words(uncased=True)
# Source: https://github.com/shmsw25/qa-hard-em/blob/master/prepro_util.py
def strip_accents(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)