Added Pretty Printing feature to Binary Tree Programs (OmkarPathak#17)

* Added some more functions to BinarySearchTree.
-> Defining intial elements of newly created Trees
-> Prettyprinting trees with left-right order and * representing null nodes.

* Added pretty print to BinaryTree.py

* Fixed flake8 Linting

Author: hanif-ali

Programs/P43_BinarySearchTree.py

@@ -72,9 +72,13 @@ def postorder(self):
             print(str(self.data), end = ' ')
 
 class Tree(object):
-    def __init__(self):
+    def __init__(self, initial_data = []):
         self.root = None
 
+        # If provided, add initial data
+        for data in initial_data:
+            self.insert(data)
+
     def insert(self, data):
         if self.root:
             return self.root.insert(data)
@@ -106,6 +110,22 @@ def postorder(self):
             print('Postorder: ')
             self.root.postorder()
 
+
+    def pprint(self, head_node=0, _pre="", _last=True, term=False):
+
+        head_node = self.root if head_node == 0 else head_node
+
+        data = "*" if head_node is None else head_node.data
+
+        print(_pre, "`- " if _last else "|- ", data, sep="")
+        _pre += "   " if _last else "|  "
+
+        if term: return
+
+        for i, child in enumerate([head_node.leftChild, head_node.rightChild]):
+            self.pprint(child,  _pre, bool(i) ,term=not(bool(child)))
+
+
 if __name__ == '__main__':
     tree = Tree()
     tree.insert(10)
@@ -117,6 +137,7 @@ def postorder(self):
     tree.insert(7)
     tree.insert(15)
     tree.insert(13)
+    tree.pprint()
     print(tree.find(1))
     print(tree.find(12))
     tree.preorder()

Programs/P62_BinaryTree.py

@@ -38,18 +38,39 @@ def insertLeft(self,newnodeData):
             tree.left = self.left
 
 
+
+
 def printTree(tree):
         if tree != None:
             printTree(tree.getLeftChild())
             print(tree.getnodeDataValue())
             printTree(tree.getRightChild())
 
+
+def pprint(head_node, _pre="", _last=True, term=False):
+    data = "*" if head_node is None else head_node.nodeData
+
+    print(_pre, "`- " if _last else "|- ", data, sep="")
+    _pre += "   " if _last else "|  "
+
+    if term: return
+
+    left = head_node.getLeftChild()
+    right = head_node.getRightChild()
+
+    for i, child in enumerate([left, right]):
+        pprint(child,  _pre, bool(i) ,term=not(bool(child)))
+
+
+
+
 def testTree():
     myTree = BinaryTree("1")
     myTree.insertLeft("2")
     myTree.insertRight("3")
     myTree.insertRight("4")
     printTree(myTree)
+    pprint(myTree)
 
 if __name__ == '__main__':
     testTree()