spaCy/spacy/tokens/span.pyx

211 lines
6.9 KiB
Cython

from __future__ import unicode_literals
from collections import defaultdict
import numpy
import numpy.linalg
cimport numpy as np
import math
import six
from ..structs cimport TokenC, LexemeC
from ..typedefs cimport flags_t, attr_t
from ..attrs cimport attr_id_t
from ..parts_of_speech cimport univ_pos_t
from ..util import normalize_slice
from .doc cimport token_by_start, token_by_end
cdef class Span:
"""A slice from a Doc object."""
def __cinit__(self, Doc tokens, int start, int end, int label=0, vector=None,
vector_norm=None):
if not (0 <= start <= end <= len(tokens)):
raise IndexError
self.doc = tokens
self.start = start
self.start_char = self.doc[start].idx if start < self.doc.length else 0
self.end = end
if end >= 1:
self.end_char = self.doc[end - 1].idx + len(self.doc[end - 1])
else:
self.end_char = 0
self.label = label
self._vector = vector
self._vector_norm = vector_norm
def __richcmp__(self, Span other, int op):
# Eq
if op == 0:
return self.start_char < other.start_char
elif op == 1:
return self.start_char <= other.start_char
elif op == 2:
return self.start_char == other.start_char and self.end_char == other.end_char
elif op == 3:
return self.start_char != other.start_char or self.end_char != other.end_char
elif op == 4:
return self.start_char > other.start_char
elif op == 5:
return self.start_char >= other.start_char
def __len__(self):
self._recalculate_indices()
if self.end < self.start:
return 0
return self.end - self.start
def __repr__(self):
if six.PY3:
return self.text
return self.text.encode('utf-8')
def __getitem__(self, object i):
self._recalculate_indices()
if isinstance(i, slice):
start, end = normalize_slice(len(self), i.start, i.stop, i.step)
return Span(self.doc, start + self.start, end + self.start)
else:
if i < 0:
return self.doc[self.end + i]
else:
return self.doc[self.start + i]
def __iter__(self):
self._recalculate_indices()
for i in range(self.start, self.end):
yield self.doc[i]
def merge(self, unicode tag, unicode lemma, unicode ent_type):
self.doc.merge(self.start_char, self.end_char, tag, lemma, ent_type)
def similarity(self, other):
if self.vector_norm == 0.0 or other.vector_norm == 0.0:
return 0.0
return numpy.dot(self.vector, other.vector) / (self.vector_norm * other.vector_norm)
cpdef int _recalculate_indices(self) except -1:
if self.end > self.doc.length \
or self.doc.c[self.start].idx != self.start_char \
or (self.doc.c[self.end-1].idx + self.doc.c[self.end-1].lex.length) != self.end_char:
start = token_by_start(self.doc.c, self.doc.length, self.start_char)
if self.start == -1:
raise IndexError("Error calculating span: Can't find start")
end = token_by_end(self.doc.c, self.doc.length, self.end_char)
if end == -1:
raise IndexError("Error calculating span: Can't find end")
self.start = start
self.end = end + 1
property vector:
def __get__(self):
if self._vector is None:
self._vector = sum(t.vector for t in self) / len(self)
return self._vector
property vector_norm:
def __get__(self):
cdef float value
if self._vector_norm is None:
self._vector_norm = 1e-20
for value in self.vector:
self._vector_norm += value * value
self._vector_norm = math.sqrt(self._vector_norm)
return self._vector_norm
property text:
def __get__(self):
text = self.text_with_ws
if self[-1].whitespace_:
text = text[:-1]
return text
property text_with_ws:
def __get__(self):
return u''.join([t.text_with_ws for t in self])
property root:
"""The first ancestor of the first word of the span that has its head
outside the span.
For example:
>>> toks = nlp(u'I like New York in Autumn.')
Let's name the indices --- easier than writing "toks[4]" etc.
>>> i, like, new, york, in_, autumn, dot = range(len(toks))
The head of 'new' is 'York', and the head of 'York' is 'like'
>>> toks[new].head.orth_
'York'
>>> toks[york].head.orth_
'like'
Create a span for "New York". Its root is "York".
>>> new_york = toks[new:york+1]
>>> new_york.root.orth_
'York'
When there are multiple words with external dependencies, we take the first:
>>> toks[autumn].head.orth_, toks[dot].head.orth_
('in', like')
>>> autumn_dot = toks[autumn:]
>>> autumn_dot.root.orth_
'Autumn'
"""
def __get__(self):
self._recalculate_indices()
# This should probably be called 'head', and the other one called
# 'gov'. But we went with 'head' elsehwhere, and now we're stuck =/
cdef const TokenC* start = &self.doc.c[self.start]
cdef const TokenC* end = &self.doc.c[self.end]
head = start
while start <= (head + head.head) < end and head.head != 0:
head += head.head
return self.doc[head - self.doc.c]
property lefts:
"""Tokens that are to the left of the Span, whose head is within the Span."""
def __get__(self):
for token in reversed(self): # Reverse, so we get the tokens in order
for left in token.lefts:
if left.i < self.start:
yield left
property rights:
"""Tokens that are to the right of the Span, whose head is within the Span."""
def __get__(self):
for token in self:
for right in token.rights:
if right.i >= self.end:
yield right
property subtree:
def __get__(self):
for word in self.lefts:
yield from word.subtree
yield from self
for word in self.rights:
yield from word.subtree
property orth_:
def __get__(self):
return ''.join([t.string for t in self]).strip()
property lemma_:
def __get__(self):
return ' '.join([t.lemma_ for t in self]).strip()
property string:
def __get__(self):
return ''.join([t.string for t in self])
property label_:
def __get__(self):
return self.doc.vocab.strings[self.label]