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 #!/usr/bin/env python
 2 # -*-coding: UTF-8-*-
 3 
 4 #构建节点
 5 class Node:
 6   def __init__(self):
 7     self.map = {}
 8   def contain(self,key):
 9     return self.map.__contains__(key)
10   def __getitem__(self,key):
11     return self.map[key]
12   def __setitem__(self,key,value):
13     self.map[key]=value
14     
15 class Item:
16   def __init__(self,key):
17     self.key=key
18     self.subNum=0
19     self.subNode=Node()
20   def add(self,key,item):
21     self.subNum += 1
22     self.subNode[key] = item
23 
24 #建树
25 def build_tree(input):
26   """build a tree"""
27   sock = open(input,"r")
28   buf = sock.read()
29   buf = chinese(buf)
30   tree = Item(" ")
31   for word in buf:
32     current = tree
33     for x in word:
34       if current.subNode.contain(x):
35         current = current.subNode[x]
36       else:
37         item = Item(x)
38         current.add(x,item)
39         current = item
40   print tree
41   return tree
42 
43 def search(buf,thefile):
44   "search."
45   buf = chinese(buf)
46   tree = build_tree(thefile)
47   havefind = ""
48   for word in buf:
49     current = tree
50     for x in word:
51       if current.subNode.contain(x):
52         current = current.subNode[x]
53         if  current.subNum == 0:
54           havefind += "".join(word)
55       else:
56         break
57   return havefind
58 
59 #判断读入的是否为汉字
60 def chinese(input):
61   "remove the not chinese"
62   input = unicode(input,"utf8")
63   buf = []
64   for word in input:
65     if word >= u'u4e00' and word <= u'u9fa5':
66       buf = buf+[word.encode('utf-8')]
67   return buf
68 
69 
70 def run():
71   fileName = "test"
72   textChar = "我"
73   buf = search(textChar,fileName)
74   print buf
75 
76 if __name__ == "__main__":
77   run()

有关字典树的理论和概念可以参见http://blog.csdn.net/v_july_v/article/details/6897097
有关python的建树过程http://bytes.com/topic/python/answers/827476-dictionary-tree-format-hopefully-simple

http://www.cnblogs.com/wangfupeng1988/archive/2011/04/12/2013860.html