def find_sub(self, t: Tree):
"""
Recursively finds words/phrases (refer to them as 'components') that are joined by a 'CC' symbol and that
describe a subject.
:param t: an nltk.tree.Tree
:returns: list of nltk.tree.Tree
"""
# recursion ends once 'CC' symbol is found or leaves are reached.
subtrees = []
if t.height() > 2:
# if tree height == 2, we only have leaves (string type) left in the tree.
child_labels = self.get_child_labels(t)
try:
cc_index = child_labels.index('CC')
except ValueError:
cc_index = None
if cc_index:
if t[cc_index].leaves()[0].lower() not in ['or', 'nor']:
subtrees.append(t)
else:
for child in t:
if type(child) == Tree:
if child.label() != 'SBAR':
# can't remember what this condition is for.
result = self.find_sub(child) # recurse deeper.
subtrees.extend(result) # accumulate results.
return subtrees
def coref_replace(event_dict, key):
"""
Function to replace pronouns with the referenced noun phrase. Iterates
over each sentence in a news story and pulls coreference information
from the applicable sentence, even if it is from another sentence. Also
keeps track of any changes in indexes made by replacing pronouns, i.e.,
the reference is longer than the reference so the tree index changes for
future references. Filters coreferences on various dimensions to ensure
only "good" coreferences are replaced. The default behavior is to do
no replacement rather than a bad replacement. The function does not
return a value, instead the event_dict is updated with the new parse tree
containing the coref information.
Parameters
----------
event_dict: Dictionary.
Dictionary of sentence information, such as produced by
utilities.parse_sents().
key: String.
ID of the event or news story being processed.
"""
#TODO: This could use some major refactoring.
if 'coref_info' in event_dict[key]['sent_info'].keys():
sent_info = event_dict[key]['sent_info']['sents']
coref_info = event_dict[key]['sent_info']['coref_info']
for sent in coref_info:
for coref in coref_info[sent]['corefs']:
pronoun = coref[0]
ref = coref[1]
if any([word in ref[0] for word in pronoun[0].split()]):
pass
elif any([word in pronoun[0] for word in ref[0].split()]):
pass
elif pronoun[4] - pronoun[3] > 1:
pass
else:
try:
#Getting the stuff for pronouns
if 'coref_tree' in sent_info[pronoun[1]].keys():
pronoun_sent = copy.deepcopy(sent_info[pronoun[1]]
['coref_tree'])
else:
pronoun_sent = copy.deepcopy(sent_info[pronoun[1]]
['parse_tree'])
pronoun_sent = Tree(pronoun_sent)
pro_shift = coref_info[pronoun[1]]['shift']
#Getting stuff for the reference
if 'coref_tree' in sent_info[ref[1]].keys():
coref_sent = sent_info[ref[1]]['coref_tree']
else:
coref_sent = Tree(sent_info[ref[1]]['parse_tree'])
ref_shift = coref_info[ref[1]]['shift']
#Actaully replacing the pronoun
try:
pronoun_pos = pronoun_sent.leaf_treeposition(pronoun[3]
+ pro_shift)
#Hunting for the right pronoun
if pronoun_sent[pronoun_pos] != pronoun[0]:
if pronoun_sent[pronoun_sent.leaf_treeposition(pronoun[3] + (pro_shift - 1))] == pronoun[0]:
pronoun_pos = pronoun_sent.leaf_treeposition(pronoun[3] + (pro_shift - 1))
coref_info[pronoun[1]]['shift'] -= 1
elif pronoun_sent[pronoun_sent.leaf_treeposition(pronoun[3] + (pro_shift + 1))] == pronoun[0]:
pronoun_pos = pronoun_sent.leaf_treeposition(pronoun[3] + (pro_shift + 1))
coref_info[pronoun[1]]['shift'] += 1
else:
break
#Hunting for the right coref
original_coref_index = coref_sent.leaf_treeposition(ref[3])[:-2]
if ' '.join(coref_sent[original_coref_index].leaves()) == ref[0]:
coref_pos = coref_sent.leaf_treeposition(ref[3])[:-2]
elif ref[0] in ' '.join(coref_sent[original_coref_index].leaves()):
coref_pos = coref_sent.leaf_treeposition(ref[3])[:-2]
else:
coref_pos = coref_sent.leaf_treeposition(ref[3] + ref_shift)[:-2]
if ref[0] not in ' '.join(coref_sent[coref_pos].leaves()):
pass
#Found everything, now replace
coref_tree = Tree('COREF', [coref_sent[coref_pos]])
pronoun_sent[pronoun_pos[:-1]] = coref_tree
except IndexError:
#TODO: Should this use the original sentence rather
#than possibly bad coreferences?
print """Key {}, sentence {} has a problem with the corefencing. Breaking and moving on.\n""".format(key, sent)
break
#Recording the shift length for the pronoun replacement
if len(coref_tree.leaves()) <= 2:
coref_info[pronoun[1]]['shift'] += 0
else:
coref_info[pronoun[1]]['shift'] += coref_tree.height()
coref_info[pronoun[1]]['errors'].append(False)
if not any(coref_info[pronoun[1]]['errors']):
if pronoun_sent != sent_info[sent]['parse_tree']:
sent_info[sent]['coref_tree'] = pronoun_sent
except RuntimeError, e:
print 'There was an error. {}'.format(e)
coref_info[pronoun[1]]['errors'].append(True)
pass
