Added linked list class.

linked-lists/linked_list.py

@@ -0,0 +1,75 @@
+
+class Node(object):
+    def __init__(self, data):
+        self.next = None
+        self.data = data
+        
+    def __str__(self):
+        return self.data
+
+class LinkedList(object):
+    def __init__(self, head):
+        self.head = head
+
+    def __len__(self):
+        curr = self.head
+        counter = 0
+        while curr is not None:
+            counter += 1
+            curr = curr.next
+        return counter
+    
+    def insert_to_front(self, data):
+        if data is None:
+            return
+        node = Node(data)
+        if self.head is None:
+            self.head = node
+        else:
+            node.next = self.head
+            self.head = node
+            
+    def append(self, data):
+        if data is None:
+            return
+        node = Node(data)
+        if self.head is None:
+            self.head = node
+        else:
+            curr_node = self.head
+            while curr_node.next is not None:
+                curr_node = curr_node.next
+            curr_node.next = node
+            
+    def find(self, data):
+        if data is None:
+            return
+        if self.head is None:
+            return
+        curr_node = self.head
+        while curr_node is not None:
+            if curr_node.data == data:
+                return curr_node
+            else:
+                curr_node = curr_node.next
+                
+    def delete(self, data):
+        if data is None:
+            return
+        if self.head is None:
+            return
+        prev_node = self.head
+        curr_node = prev_node.next
+        while curr_node is not None:
+            if curr_node.data == data:
+                prev_node.next = curr_node.next
+                return
+            else:
+                prev_node = curr_node
+                curr_node = curr_node.next
+
+    def print_list(self):
+        curr_node = self.head
+        while curr_node is not None:
+            print(curr_node.data)
+            curr_node = curr_node.next