python之数据结构链表实现方式

 #!/usr/bin/env python
 # ---------------------------------------
 # author : Geng Jie
 # email  : [e-mail]
 #
 # Create Time: 2016/3/16 22:05
 # ----------------------------------------

 class Node():
     def __init__(self, data):
         self.data = data
         self.next = None

 class LinkedList:
     def __init__(self):
         self.head = None
         self.tail = None

     def append(self, data):
         node = Node(data)
         if self.head is None:
             self.head = node
             self.tail = node

         else:
             self.tail.next = node
             self.tail = node

     def is_zero(self):
         if self.head is None:
             return True
         return False

     def len(self):
         if self.head is None:
             return 'Empty'
         else:
             count = 0
             while self.head:
                 self.head = self.head.next
                 count += 1
             return count

     def iter(self):
         if not self.head:
             return

         cur = self.head
         yield cur.data
         while cur.next:
             cur = cur.next
             yield cur.data

     def insert(self, idx, value):
         cur = self.head
         cur_idx = 0
         while cur_idx < idx - 1:
             cur = cur.next
             if cur is None:
                 raise Exception('List length less than index')
             cur_idx += 1
         node = Node(value)
         node.next = cur.next
         cur.next = node
         if node.next is None:
             self.tail = node

     def remove(self, idx):
         cur = self.head
         cur_idx = 0
         while cur_idx < idx - 1:
             cur = cur.next
             if cur is None:
                 raise Exception('List length less than index')
             cur_idx += 1
         cur.next = cur.next.next
         if cur.next is None:
             self.tail = cur

 if __name__ == '__main__':
     linked_list = LinkedList()
     for i in range(10):
         linked_list.append(i)

     print(linked_list.len())

     # print(linked_list.is_zero())
     # linked_list.insert(3, 30)
     # linked_list.remove(4)
     # for node in linked_list.iter():
     #     print(node)