python 单链表操作

 1 class Node():     # 初始化 构造函数  
 2     def __init__(self,value,next=None):  
 3         self.value=value  
 4         self.next=next  
 5   
 6 def Creatlist(n):  
 7     if n<=0:  
 8         return False  
 9     if n==1:  
10         return Node(1)    # 只有一个节点  
11     else:  
12         root=Node(1)  
13         tmp=root  
14         for i in range(2,n+1):       #  一个一个的增加节点  
15             tmp.next=Node(i)  
16             tmp=tmp.next  
17     return root            # 返回根节点  
18   
19 def printlist(head):       # 打印链表  
20     p=head  
21     while p!=None:  
22         print p.value  
23         p=p.next  
24   
25 def listlen(head):       # 链表长度  
26     c=0  
27     p=head  
28     while p!=None:  
29         c=c+1  
30         p=p.next  
31     return c  
32   
33 def insert(head,n):         # 在n的前面插入元素  
34     if n<1 or n>listlen(head):  
35         return  
36   
37     p=head  
38     for i in range(1,n-1):  # 循环四次到达 5  
39         p=p.next  
40     a=raw_input("Enter a value:")  
41     t=Node(value=a)  
42     t.next=p.next     # 这里注意  
43     p.next=t  
44     return head       # 把6放在t的后面 t放在原先p的后面  
45   
46 def dellist(head,n):  # 删除链表  
47     if n<1 or n>listlen(head):  
48         return head  
49     elif n is 1:  
50         head=head.next   # 删除头  
51     else:  
52         p=head  
53         for i in range(1,n-1):    
54             p=p.next     # 循环到达 2次   
55         q=p.next  
56         p.next=q.next    # 把5放在3的后面  
57     return head  
58   
59   
60 def main():  
61     print "Create a linklist"  
62     head=Creatlist(7)  
63     printlist(head)  
64     print  
65     print "___________________________"  
66   
67     n1=raw_input("Enter the index to insert")  
68     n1=int(n1)  
69     insert(head,n1)  
70     printlist(head)  
71     print  
72     print "___________________________"  
73   
74     n2=raw_input("Enter the index to delete")  
75     n2=int(n2)  
76     dellist(head,n2)  
77     printlist(head)  
78   
79   
80 if __name__==‘__main__‘:  main()   # 主函数调用

run C:\\Anaconda\\node.py
Create a linklist
1
2
3
4
5
6
7

___________________________

Enter the index to insert 6

Enter a value:99
1
2
3
4
5
99
6
7

___________________________

Enter the index to delete 4
1
2
3
5
99
6
7