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：

复制代码 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  

def removeFromFront(self):
"""Delete node from front of list"""

  if self.isEmpty():  # raise exception on empty list  
     raise IndexError, "remove from empty list"  

  tempNode = self._firstNode  

  if self._firstNode is self._lastNode:  # one node in list  
     self._firstNode = self._lastNode = None  
  else:  
     self._firstNode = self._firstNode._nextNode  

  return tempNode  

def removeFromBack(self):
"""Delete node from back of list"""

  if self.isEmpty():  # raise exception on empty list  
     raise IndexError, "remove from empty list"  

  tempNode = self._lastNode  

  if self._firstNode is self._lastNode:  # one node in list  
     self._firstNode = self._lastNode = None  
  else:  
     currentNode = self._firstNode  

     # locate second-to-last node  
     while currentNode._nextNode is not self._lastNode:  
           currentNode = currentNode._nextNode  

     currentNode._nextNode = None  
     self._lastNode = currentNode  

  return tempNode  

def isEmpty(self):
"""Returns true if List is empty"""

  return self._firstNode is None

希望本文所述对大家的Python程序设计有所帮助。