added DoublyLinkedList.py code

Author: joeyajames

DoublyLinkedList.py

@@ -0,0 +1,78 @@
+class Node(object):
+
+    def __init__ (self, d, n = None, p = None):
+        self.data = d
+        self.next_node = n
+        self.prev_node = p
+
+    def get_next (self):
+        return self.next_node
+
+    def set_next (self, n):
+        self.next_node = n
+
+    def get_prev (self):
+        return self.prev_node
+
+    def set_prev (self, p):
+        self.prev_node = p
+
+    def get_data (self):
+        return self.data
+
+    def set_data (self, d):
+        self.data = d
+
+
+class LinkedList (object):
+
+    def __init__(self, r = None):
+        self.root = r
+        self.size = 0
+
+    def get_size (self):
+        return self.size
+
+    def add (self, d):
+        new_node = Node (d, self.root)
+        if self.root:
+            self.root.set_prev(new_node)
+        self.root = new_node
+        self.size += 1
+
+    def remove (self, d):
+        this_node = self.root
+
+        while this_node:
+            if this_node.get_data() == d:
+                next = this_node.get_next()
+                prev = this_node.get_prev()
+                
+                if next:
+                    next.set_prev(prev)
+                if prev:
+                    prev.set_next(next)
+                else:
+                    self.root = this_node
+                self.size -= 1
+                return True		# data removed
+            else:
+                this_node = this_node.get_next()
+        return False  # data not found
+
+    def find (self, d):
+        this_node = self.root
+        while this_node:
+            if this_node.get_data() == d:
+                return d
+            else:
+                this_node = this_node.get_next()
+        return None
+
+myList = LinkedList()
+myList.add(5)
+myList.add(8)
+myList.add(12)
+myList.remove(8)
+print(myList.remove(12))
+print(myList.find(5))