Create linked_list.py

Author: learning-zone

linked_list.py

@@ -0,0 +1,100 @@
+""" Implement a singly linked list. """
+
+class Node(object):
+    """ Creates a node. """
+
+    def __init__(self, data=None, nxt=None):
+        self.data = data
+        self.next = nxt
+
+
+
+class LinkedList(object):
+    """ Creates a linked list. """
+
+    def __init__(self, head=None):
+        self.head = head
+        self.tail = tail
+
+    def insert(self, data, position):
+        """ Takes data as an input and a position and adds it to the linked list as a node before that position. """
+
+        new_node = Node(data)
+
+        if position == 0:
+            new_node.next = self.head
+            self.head = new_node
+
+        if position == self.size():
+            self.tail.next = new_node
+            self.tail = new_node
+
+
+        prev = None
+        curr = self.head
+        index = 0
+
+        while curr.next:
+            if position == index:
+                prev.next = new_node
+                new_node.next = curr
+                return
+            index +=1
+            prev = prev.next
+            curr = curr.next
+
+
+    def size(self):
+        """ Returns the length of the linked list. """
+
+        size = 0
+
+        if head is None and tail is None:
+            return size
+
+        curr = self.head
+
+        while curr:
+            size += 1
+            curr = curr.next
+
+        return size
+
+
+    def search(self, data):
+        """ Takes data as an input and returns the node holding the data. """
+
+        curr = self.head
+
+        while curr:
+            if curr.data == data:
+                return curr
+            curr = curr.next
+
+        raise ValueError('Data not in linked list.')
+
+
+    def delete(self, data):
+        """ Takes data as an input and deletes the node with that data. """
+
+        prev = None
+        curr = self.head
+
+        while curr:
+            if curr.data == data:
+                if curr == self.head:
+                    self.head = curr.next
+                else:
+                    prev.next = curr.next
+
+            prev = curr
+            curr = curr.next
+
+        if curr is None:
+            raise ValueError('Data not in linked list.')
+
+
+
+
+
+