Source Code for Module nltk.corpus.reader.ppattach

 1  # Natural Language Toolkit: PP Attachment Corpus Reader 
 2  # 
 3  # Copyright (C) 2001-2011 NLTK Project 
 4  # Author: Steven Bird <sb@ldc.upenn.edu> 
 5  #         Edward Loper <edloper@gradient.cis.upenn.edu> 
 6  # URL: <http://www.nltk.org/> 
 7  # For license information, see LICENSE.TXT 
 8   
 9  """ 
10  Read lines from the Prepositional Phrase Attachment Corpus. 
11   
12  The PP Attachment Corpus contains several files having the format: 
13   
14  sentence_id verb noun1 preposition noun2 attachment 
15   
16  For example: 
17   
18  42960 gives authority to administration V 
19  46742 gives inventors of microchip N 
20   
21  The PP attachment is to the verb phrase (V) or noun phrase (N), i.e.: 
22   
23  (VP gives (NP authority) (PP to administration)) 
24  (VP gives (NP inventors (PP of microchip))) 
25   
26  The corpus contains the following files: 
27   
28  training:   training set 
29  devset:     development test set, used for algorithm development. 
30  test:       test set, used to report results 
31  bitstrings: word classes derived from Mutual Information Clustering for the Wall Street Journal. 
32   
33  Ratnaparkhi, Adwait (1994). A Maximum Entropy Model for Prepositional 
34  Phrase Attachment.  Proceedings of the ARPA Human Language Technology 
35  Conference.  [http://www.cis.upenn.edu/~adwait/papers/hlt94.ps] 
36   
37  The PP Attachment Corpus is distributed with NLTK with the permission 
38  of the author. 
39  """        
40   
41  import codecs 
42   
43  from util import * 
44  from api import * 
45   
46 -class PPAttachment: 
47 -    def __init__(self, sent, verb, noun1, prep, noun2, attachment): 
48          self.sent = sent 
49          self.verb = verb 
50          self.noun1 = noun1 
51          self.prep = prep 
52          self.noun2 = noun2 
53          self.attachment = attachment 
54   
55 -    def __repr__(self): 
56          return ('PPAttachment(sent=%r, verb=%r, noun1=%r, prep=%r, ' 
57                  'noun2=%r, attachment=%r)' % 
58                  (self.sent, self.verb, self.noun1, self.prep, 
59                   self.noun2, self.attachment)) 
60   
61 -class PPAttachmentCorpusReader(CorpusReader): 
62      """ 
63      sentence_id verb noun1 preposition noun2 attachment 
64      """ 
65 -    def attachments(self, fileids): 
66          return concat([StreamBackedCorpusView(fileid, self._read_obj_block, 
67                                                encoding=enc) 
68                         for (fileid, enc) in self.abspaths(fileids, True)]) 
69   
70 -    def tuples(self, fileids): 
71          return concat([StreamBackedCorpusView(fileid, self._read_tuple_block, 
72                                                encoding=enc) 
73                         for (fileid, enc) in self.abspaths(fileids, True)]) 
74   
75 -    def raw(self, fileids=None): 
76          if fileids is None: fileids = self._fileids 
77          elif isinstance(fileids, basestring): fileids = [fileids] 
78          return concat([self.open(f).read() for f in fileids]) 
79   
80 -    def _read_tuple_block(self, stream): 
81          line = stream.readline() 
82          if line: 
83              return [tuple(line.split())] 
84          else: 
85              return [] 
86   
87 -    def _read_obj_block(self, stream): 
88          line = stream.readline() 
89          if line: 
90              return [PPAttachment(*line.split())] 
91          else: 
92              return [] 
93