title: How to tack on value with Binary Search Tree
body: <p>I am working with a binary search tree in Python 3.2.3 and here are my two files (given from teacher) for creating the binary search tree.</p>
  
  <p>But first I will explain the problem I am having. First I am reading in the file and attaching the new words to the BST with the movie titles as their values. However I am having problems on what to do with my else statement. I believe I need to attach that word that is already in the Binary search  tree, Lets say "A" because it appears alot and attach it to another value of a movie title so that one key is attached to multiple values.</p>
  
  <p>I don't know how to go about it and it is where the else statement is in my Read function. Any help would be greatly appreciated.</p>
  
  <p>Thank you</p>
  
  <p>Tree Node:</p>
  
  <pre><code>class TreeNode:
     def __init__(self,key,val,left=None,right=None,
                                         parent=None):
        self.key = key
        self.payload = val
        self.leftChild = left
        self.rightChild = right
        self.parent = parent
  
     def hasLeftChild(self):
        return self.leftChild
  
     def hasRightChild(self):
        return self.rightChild
  
     def isLeftChild(self):
        return self.parent and \
               self.parent.leftChild == self
  
     def isRightChild(self):
        return self.parent and \
               self.parent.rightChild == self
  
     def isRoot(self):
        return not self.parent
  
     def isLeaf(self):
        return not (self.rightChild or self.leftChild)
  
     def hasAnyChildren(self):
        return self.rightChild or self.leftChild
  
     def hasBothChildren(self):
        return self.rightChild and self.leftChild
  
     def replaceNodeData(self,key,value,lc,rc):
        self.key = key
        self.payload = value
        self.leftChild = lc
        self.rightChild = rc
        if self.hasLeftChild():
            self.leftChild.parent = self
        if self.hasRightChild():
            self.rightChild.parent = self
  
     def __iter__(self):
  
        if self:
           if self.hasLeftChild():
                for elem in self.leftChild:
                   yield elem
           yield self.key
           if self.hasRightChild():
                for elem in self.rightChild:
                   yield elem
  
     def findSuccessor(self):
        succ = None
        if self.hasRightChild():
            succ = self.rightChild.findMin()
        else:
            if self.parent:
                if self.isLeftChild():
                    succ = self.parent
                else:
                    self.parent.rightChild = None
                    succ = self.parent.findSuccessor()
                    self.parent.rightChild = self
        return succ
  
     def findMin(self):
        current = self
        while current.hasLeftChild():
            current = current.leftChild
        return current
  
     def spliceOut(self):
        if self.isLeaf():
           if self.isLeftChild():
              self.parent.leftChild = None
           else:
              self.parent.rightChild = None
        elif self.hasAnyChildren():
           if self.hasLeftChild():
              if self.isLeftChild():
                 self.parent.leftChild = self.leftChild
              else:
                 self.parent.rightChild = self.leftChild
              self.leftChild.parent = self.parent
           else:
              if self.isLeftChild():
                 self.parent.leftChild = self.rightChild
              else:
                 self.parent.rightChild = self.rightChild
              self.rightChild.parent = self.parent
  </code></pre>
  
  <p>Binary Search Tree:</p>
  
  <pre><code>from tree_node import TreeNode
  
  class BinarySearchTree:
  
      def __init__(self):
          self.root = None
          self.size = 0
  
      def length(self):
          return self.size
  
      def __len__(self):
          return self.size
  
      def __iter__(self):
          return self.root.__iter__()
  
      def __str__(self):
          """Returns a string representation of the tree
             rotated 90 degrees counter-clockwise"""
  
          def strHelper(root, level):
              resultStr = ""
              if root:
                  resultStr += strHelper(root.rightChild, level+1)
                  resultStr += "| " * level
                  resultStr += str(root.key) + "\n"
                  resultStr += strHelper(root.leftChild, level+1)                
              return resultStr
  
  
          return strHelper(self.root, 0)
  
  
      def __contains__(self,key):
          if self._get(key,self.root):
              return True
          else:
              return False
  
      def get(self,key):
          if self.root:
              res = self._get(key,self.root)
              if res:
                  return res.payload
              else:
                  return None
          else:
              return None
  
      def _get(self,key,currentNode):
          if not currentNode:
              return None
          elif currentNode.key == key:
              return currentNode
          elif key &lt; currentNode.key:
              return self._get(key,currentNode.leftChild)
          else:
              return self._get(key,currentNode.rightChild)
  
      def __getitem__(self,key):
          return self.get(key) 
  
      def __setitem__(self,k,v):
          self.put(k,v)
  
      def put(self,key,val):
          if self.root:
              self._put(key,val,self.root)
          else:
              self.root = TreeNode(key,val)
          self.size = self.size + 1
  
      def _put(self,key,val,currentNode):
          if key &lt; currentNode.key:
              if currentNode.hasLeftChild():
                  self._put(key,val,currentNode.leftChild)
              else:
                  currentNode.leftChild = TreeNode(key,val,
                                            parent=currentNode)
          else:
              if currentNode.hasRightChild():
                  self._put(key,val,currentNode.rightChild)
              else:
                  currentNode.rightChild = TreeNode(key,val,
                                            parent=currentNode)
  
      def delete(self,key):
        if self.size &gt; 1:
            nodeToRemove = self._get(key,self.root)
            if nodeToRemove:
                self.remove(nodeToRemove)
                self.size = self.size-1
            else:
                raise KeyError('Error, key not in tree')
        elif self.size == 1 and self.root.key == key:
            self.root = None
            self.size = self.size - 1
        else:
            raise KeyError('Error, key not in tree')
  
      def __delitem__(self,key):
          self.delete(key)
  
  
      def remove(self,currentNode):
        if currentNode.isLeaf(): #leaf
          if currentNode == currentNode.parent.leftChild:
              currentNode.parent.leftChild = None
          else:
              currentNode.parent.rightChild = None
        elif currentNode.hasBothChildren(): #interior
          succ = currentNode.findSuccessor()
          succ.spliceOut()
          currentNode.key = succ.key
          currentNode.payload = succ.payload
  
        else: # this node has one child
          if currentNode.hasLeftChild():
            if currentNode.isLeftChild():
                currentNode.leftChild.parent = currentNode.parent
                currentNode.parent.leftChild = currentNode.leftChild
            elif currentNode.isRightChild():
                currentNode.leftChild.parent = currentNode.parent
                currentNode.parent.rightChild = currentNode.leftChild
            else:
                currentNode.replaceNodeData(currentNode.leftChild.key,
                                   currentNode.leftChild.payload,
                                   currentNode.leftChild.leftChild,
                                   currentNode.leftChild.rightChild)
  
          else:
            if currentNode.isLeftChild():
                currentNode.rightChild.parent = currentNode.parent
                currentNode.parent.leftChild = currentNode.rightChild
            elif currentNode.isRightChild():
                currentNode.rightChild.parent = currentNode.parent
                currentNode.parent.rightChild = currentNode.rightChild
            else:
                currentNode.replaceNodeData(currentNode.rightChild.key,
                                   currentNode.rightChild.payload,
                                   currentNode.rightChild.leftChild,
                                   currentNode.rightChild.rightChild)
  
  
  
  
  def main():
      t = BinarySearchTree()
      t.put(5,5)
      t.put(3,3)
      t.put(8,8)
      t.put(10, 10)
      t.put(7,7)
      print(t)
  
      return t
  
  if __name__ == "__main__": t = main()
  </code></pre>
  
  <p>My Code that I need help with:</p>
  
  <pre><code>from binary_search_tree import BinarySearchTree
  from tree_node import TreeNode
  
  MovieTree = BinarySearchTree()
  MovieList = []
  
  def Read(filename):
      file = open('movieData.txt')
      for line in file:
          line = line.strip()
          words = line.lower().split(' ')
          for word in words:
              if word not in MovieTree:
                  MovieTree.put(word, [line])
              else:
                  pass
                  #attach word that is already in BST to another value
                  # which is this case is a movie title.
  
  def Main():
      Read('movieData.txt')
      #print(MovieTree)
      #print (MovieList)
  
  Main()
  </code></pre>
  
  <p>And if needed here is a small sample of what I am reading in:</p>
  
  <pre><code>A Bad Day &lt;2006&gt;
  A Baleia Branca - Uma Ideia de Deus &lt;2007&gt;
  A Batalha das Flores no Campo Grande &lt;1907&gt;
  A Bear Named Winnie &lt;2004&gt;
  A Beautiful Daze &lt;2008&gt;
  A Beautiful Mind &lt;2001&gt;
  A Bell for Adano &lt;1945&gt;
  A Better Place &lt;1997&gt;
  A Big Hand for Sooty &lt;1998&gt;
  A Big Hand for the Little Lady &lt;1966&gt;
  A Big Mistake! &lt;2009&gt;
  A Bill of Divorcement &lt;1932&gt; &lt;1940&gt;
  A Bird in a Bonnet &lt;1958&gt;
  A Bird in a Guilty Cage &lt;1952&gt;
  A Bird in the Head &lt;1946&gt;
  A Bit of Scarlet &lt;1997&gt;
  A Black Widow &lt;2009&gt;
  A Blind Bargain &lt;1922&gt;
  A Blue Collapse &lt;2008&gt;
  A Blue Note &lt;2009&gt;
  </code></pre>