熊熊历险记下载,赵宗洪,太原工业学院教务网
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:
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。
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