python列表操作实例

本文实例讲述了python列表操作的方法。分享给大家供大家参考。

具体实现方法如下：

代码如下:class Node:
   """Single node in a data structure"""
 
   def __init__(self, data):
      """Node constructor"""
      
      self._data = data
      self._nextNode = None
    
   def __str__(self):
      """Node data representation"""
 
      return str(self._data)    
 
class List:
   """Linked list"""
 
   def __init__(self):
      """List constructor"""
 
      self._firstNode = None
      self._lastNode = None
 
   def __str__(self):
      """List string representation"""
 
      if self.isEmpty():
         return "empty"
 
      currentNode = self._firstNode
      output = []
 
      while currentNode is not None:
         output.append(str(currentNode._data))
         currentNode = currentNode._nextNode
 
      return " ".join(output)    
 
   def insertAtFront(self, value):
      """Insert node at front of list"""
 
      newNode = Node(value)
 
      if self.isEmpty():  # List is empty
         self._firstNode = self._lastNode = newNode
      else:   # List is not empty
         newNode._nextNode = self._firstNode
         self._firstNode = newNode
        
   def insertAtBack(self, value):
      """Insert node at back of list"""
 
      newNode = Node(value)
 
      if self.isEmpty():  # List is empty
         self._firstNode = self._lastNode = newNode
      else:  # List is not empty
         self._lastNode._nextNode = newNode
         self._lastNode = newNode