segment.py

   1 """Segment a collection of letters into words"""
   2
   3 import language_models
   4 import sys
   5 from functools import lru_cache
   6 sys.setrecursionlimit(1000000)
   7
   8 @lru_cache()
   9 def segment(text):
  10     """Return a list of words that is the best segmentation of text.
  11     """
  12     if not text: return []
  13     candidates = ([first]+segment(rest) for first, rest in splits(text))
  14     return max(candidates, key=language_models.Pwords)
  15
  16 @lru_cache()
  17 def segment_wrong(text):
  18     """Return a list of words that is the best segmentation of text.
  19     """
  20     if not text: return []
  21     candidates = ([first]+segment(rest) for first, rest in splits(text))
  22     return max(candidates, key=language_models.Pwords_wrong)
  23
  24
  25 def splits(text, L=20):
  26     """Return a list of all possible (first, rest) pairs, len(first)<=L.
  27     """
  28     return [(text[:i+1], text[i+1:])
  29             for i in range(min(len(text), L))]
  30