spaCy/spacy/lexeme.pyx
2014-08-21 16:37:13 +02:00

140 lines
4.5 KiB
Cython

# cython: profile=True
# cython: embedsignature=True
'''Accessors for Lexeme properties, given a lex_id, which is cast to a Lexeme*.
Mostly useful from Python-space. From Cython-space, you can just cast to
Lexeme* yourself.
'''
from __future__ import unicode_literals
from libc.stdlib cimport malloc, calloc, free
from libc.stdint cimport uint64_t
from spacy.spacy cimport StringHash
cpdef int set_flags(LexID lex_id, object active_flags) except *:
"""Set orthographic bit flags for a Lexeme.
Args:
lex_id (LexemeID): A reference ID for a Lexeme.
active_flags: A sequence of bits to set as True.
"""
cdef size_t flag
cdef Lexeme* w = <Lexeme*>lex_id
for flag in active_flags:
w.orth_flags |= 1 << flag
cpdef StringHash view_of(LexID lex_id, size_t view) except 0:
return (<Lexeme*>lex_id).string_views[view]
cpdef StringHash lex_of(LexID lex_id) except 0:
'''Access a hash of the word's string.
>>> lex_of(lookup(u'Hi')) == hash(u'Hi')
True
'''
return (<Lexeme*>lex_id).lex
cpdef ClusterID cluster_of(LexID lex_id) except 0:
'''Access an integer representation of the word's Brown cluster.
A Brown cluster is an address into a binary tree, which gives some (noisy)
information about the word's distributional context.
>>> strings = (u'pineapple', u'apple', u'dapple', u'scalable')
>>> token_ids = [lookup(s) for s in strings]
>>> clusters = [cluster_of(t) for t in token_ids]
>>> print ["{0:b"} % cluster_of(t) for t in token_ids]
["100111110110", "100111100100", "01010111011001", "100111110110"]
The clusterings are unideal, but often slightly useful.
"pineapple" and "apple" share a long prefix, indicating a similar meaning,
while "dapple" is totally different. On the other hand, "scalable" receives
the same cluster ID as "pineapple", which is not what we'd like.
'''
return (<Lexeme*>lex_id).cluster
cpdef char first_of(size_t lex_id) except 0:
'''Access the first byte of a utf8 encoding of the word.
>>> lex_id = lookup(u'Hello')
>>> chr(first_of(lex_id))
'H'
'''
return (<Lexeme*>lex_id).string[0]
cpdef size_t length_of(size_t lex_id) except 0:
'''Access the (unicode) length of the word.
'''
cdef Lexeme* word = <Lexeme*>lex_id
return word.length
cpdef double prob_of(size_t lex_id) except 0:
'''Access an estimate of the word's unigram log probability.
Probabilities are calculated from a large text corpus, and smoothed using
simple Good-Turing. Estimates are read from data/en/probabilities, and
can be replaced using spacy.en.load_probabilities.
>>> prob_of(lookup(u'world'))
-20.10340371976182
'''
return (<Lexeme*>lex_id).prob
DEF OFT_UPPER = 1
DEF OFT_TITLE = 2
cpdef bint is_oft_upper(size_t lex_id):
'''Check the OFT_UPPER distributional flag for the word.
The OFT_UPPER flag records whether a lower-cased version of the word
is found in all-upper case frequently in a large sample of text, where
"frequently" is defined as P >= 0.95 (chosen for high mutual information for
POS tagging).
Case statistics are estimated from a large text corpus. Estimates are read
from data/en/case_stats, and can be replaced using spacy.en.load_case_stats.
>>> is_oft_upper(lookup(u'nato'))
True
>>> is_oft_upper(lookup(u'the'))
False
'''
return (<Lexeme*>lex_id).dist_flags & (1 << OFT_UPPER)
cpdef bint is_oft_title(size_t lex_id):
'''Check the OFT_TITLE distributional flag for the word.
The OFT_TITLE flag records whether a lower-cased version of the word
is found title-cased (see string.istitle) frequently in a large sample of text,
where "frequently" is defined as P >= 0.3 (chosen for high mutual information for
POS tagging).
Case statistics are estimated from a large text corpus. Estimates are read
from data/en/case_stats, and can be replaced using spacy.en.load_case_stats.
>>> is_oft_upper(lookup(u'john'))
True
>>> is_oft_upper(lookup(u'Bill'))
False
'''
return (<Lexeme*>lex_id).dist_flags & (1 << OFT_TITLE)
cpdef bint check_orth_flag(size_t lex_id, OrthFlags flag) except *:
return (<Lexeme*>lex_id).orth_flags & (1 << flag)
cpdef bint check_dist_flag(size_t lex_id, DistFlags flag) except *:
return (<Lexeme*>lex_id).dist_flags & (1 << flag)
cpdef bint check_tag_flag(LexID lex_id, TagFlags flag) except *:
return (<Lexeme*>lex_id).possible_tags & (1 << flag)