Source Code for Module nltk.corpus.reader.ppattach

  1  # Natural Language Toolkit: PP Attachment Corpus Reader 
  2  # 
  3  # Copyright (C) 2001-2008 NLTK Project 
  4  # Author: Steven Bird <[email protected]> 
  5  #         Edward Loper <[email protected]> 
  6  # URL: <http://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  from util import * 
 42  from api import * 
 43  from nltk import tokenize 
 44  import codecs 
 45  from nltk.internals import deprecated 
 46   
 47 -class PPAttachment: 
 48 -    def __init__(self, sent, verb, noun1, prep, noun2, attachment): 
 49          self.sent = sent 
 50          self.verb = verb 
 51          self.noun1 = noun1 
 52          self.prep = prep 
 53          self.noun2 = noun2 
 54          self.attachment = attachment 
 55   
 56 -    def __repr__(self): 
 57          return ('PPAttachment(sent=%r, verb=%r, noun1=%r, prep=%r, ' 
 58                  'noun2=%r, attachment=%r)' % 
 59                  (self.sent, self.verb, self.noun1, self.prep, 
 60                   self.noun2, self.attachment)) 
 61   
 62 -class PPAttachmentCorpusReader(CorpusReader): 
 63      """ 
 64      sentence_id verb noun1 preposition noun2 attachment 
 65      """ 
 66 -    def attachments(self, files): 
 67          return concat([StreamBackedCorpusView(filename, self._read_obj_block, 
 68                                                encoding=enc) 
 69                         for (filename, enc) in self.abspaths(files, True)]) 
 70   
 71 -    def tuples(self, files): 
 72          return concat([StreamBackedCorpusView(filename, self._read_tuple_block, 
 73                                                encoding=enc) 
 74                         for (filename, enc) in self.abspaths(files, True)]) 
 75   
 76 -    def raw(self, files=None): 
 77          if files is None: files = self._files 
 78          elif isinstance(files, basestring): files = [files] 
 79          return concat([self.open(f).read() for f in files]) 
 80   
 81 -    def _read_tuple_block(self, stream): 
 82          line = stream.readline() 
 83          if line: 
 84              return [tuple(line.split())] 
 85          else: 
 86              return [] 
 87   
 88 -    def _read_obj_block(self, stream): 
 89          line = stream.readline() 
 90          if line: 
 91              return [PPAttachment(*line.split())] 
 92          else: 
 93              return [] 
 94   
 95      #{ Deprecated since 0.8 
 96      @deprecated("Use .tuples() or .raw() or .attachments() instead.") 
 97 -    def read(self, items, format='tuple'): 
 98          if format == 'tuple': return self.tuples(items) 
 99          if format == 'raw': return self.raw(items) 
100          raise ValueError('bad format %r' % format) 
101      #} 
102