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.
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.
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.
Thank you
Tree Node:
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
Binary Search Tree:
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 < 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 < 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 > 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()
My Code that I need help with:
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()
And if needed here is a small sample of what I am reading in:
A Bad Day <2006>
A Baleia Branca - Uma Ideia de Deus <2007>
A Batalha das Flores no Campo Grande <1907>
A Bear Named Winnie <2004>
A Beautiful Daze <2008>
A Beautiful Mind <2001>
A Bell for Adano <1945>
A Better Place <1997>
A Big Hand for Sooty <1998>
A Big Hand for the Little Lady <1966>
A Big Mistake! <2009>
A Bill of Divorcement <1932> <1940>
A Bird in a Bonnet <1958>
A Bird in a Guilty Cage <1952>
A Bird in the Head <1946>
A Bit of Scarlet <1997>
A Black Widow <2009>
A Blind Bargain <1922>
A Blue Collapse <2008>
A Blue Note <2009>
If I understand the requirement correctly, I think you want
MovieTree.get(word).append(line)The get(word) part returns a list of titles associated with that word (i.e. the payload from the matching word in the binary search tree), and .append(line) adds line onto the end of the list.