Python Trie

gistfile1.py

 class TrieNode:
     def __init__(self, ch, final=False):
         if ch:
             ch = ch.lower()

         self.ch = ch
         self.final = final
         self.children = {}

     def addchild(self, child):
         self.children[child.ch] = child

     def next(self, ch):
         return self.children.get(ch.lower(), None)

 def buildtrie(strings):
     return _buildtrie(TrieNode(None), (iter(s) for s in strings))

 def _buildtrie(node, chiters):
     map = {}

     for chiter in chiters:
         try:
             ch = next(chiter)
             if ch in map:
                 map[ch].append(ch)
             else:
                 map[ch] = [chiter]

         except StopIteration:
             node.final = True

     for ch, chiters in map.items():
         node.addchild(_buildtrie(TrieNode(ch), chiters))

     return node