python单链表的好多种操作
数据结构好久没有看了，基础几乎也没有，所以开始慢慢摸索学习基本的一些数据结构，去理解然后实现。下面是我学习的一些代码，如有错误还望指出来，让我及时改正
class Node(object):
def __init__(self, init_data):
self.data = init_data
self.next = None
class NewList(object):
def __init__(self):
self.head = None
def is_empty(self):
if self.head is None:
print('链表为空')
# 在链表前添加节点
def add(self, item):
temp = Node(item)
if self.head is None:
self.head = temp
else:
temp.next = self.head
self.head = temp
print(id(self.head),id(temp),id(self.head.data),id(temp.data))
def append(self, item):
temp = Node(item)
origin = self.head
if self.head is None:
self.head = temp
else:
while origin.next is not None:
origin = origin.next
else:
origin.next = temp
def search(self, item):
origin = self.head
flag = False
while origin is not None:
if origin.data == item:
print('你要找的元素在里面')
flag = True
break
else:
origin = origin.next
if flag is False:
print('未找到')
def location(self, item):
location = 0
origin = self.head
lista = []
while origin is not None:
if origin.data == item:
lista.append(location)
origin = origin.next
location += 1
print(lista)
def index(self, item):
origin = self.head
count = 0
while origin is not None:
if origin.data == item:
count += 1
break
else:
origin = origin.next
if count != 0:
print(count-1)
else:
print('未找到')
# 删除所有值为item的节点
def delete(self, item):
if self.head is None:
print('链表是空的')
else:
while True:
if self.head.data == item:
self.head = self.head.next
else:
break
previous = self.head
current = previous.next
while current is not None:
if current.data == item:
previous.next = current.next
current = current.next
continue
else:
previous = current
current = current.next
# 仿照列表中的remove方法
def remove(self, item):
flag = False
if self.head is None:
print('链表是空的')
else:
if self.head.data == item:
self.head = self.head.next
else:
previous = self.head
current = self.head.next
while flag is False:
if current.data == item:
previous.next = current.next
flag = True
else:
previous = current
current = current.next
if flag is True:
print('已经移除')
else:
print('未找到相应的数字')
# 遍历单链表中的值
def bianli(self):
current = self.head
lista = []
while current is not None:
lista.append(current.data)
current = current.next
print(lista)
# 删除链表制定位置上的节点
def delnode(self, index):
# current 代表当前位置
# previous 代表上一个位置
# 一开始都指向head
current = self.head
previous = self.head
if index == 1:
self.head = self.head.next
else:
# 用来定位指定位置,执行一次current往后挪一个，previous也后移一个
for i in range(index-1):
if current.next is None:
print('超出了范围')
break
else:
print('成功执行')
previous = current
current = current.next
# 此时current到了指定的位置上
# 未超出范围,执行删除操作
else:
previous.next = current.next
# 查看链表的长度：
def len(self):
length = 0
current = self.head
while current is not None:
length += 1
current = current.next
return length
# 有了len（）之后,删除制定节点的另一种方法
def deleNode(self, index):
if self.head is None:
print('链表为空')
elif index > self.len():
print('超出范围')
return
elif index == 1:
self.head = self.head.next
else:
previous = self.head
current = previous.next
count = 2
# 因为删除的那个节点一定存在所以while true没问题
while True:
if index == count:
previous.next = current.next
break
else:
previous = current
current = current.next
count += 1
# 指定位置前插入节点
def insert(self, index, value):
if self.head is None:
print('链表为空')
if index > self.len():
print('链表超出范围')
elif index == 1:
self.add(value)
elif index == self.len()+1:
self.append(value)
else:
count = 2
previous = self.head
current = self.head.next
while True:
if count == index:
temp = Node(value)
temp.next = current
previous.next = temp
break
else:
previous = current
current = current.next
count += 1
# 删除链表以及内部的所有元素
def clear(self):
self.head = None
# 获得指定位置节点的值
def getvalue(self, index):
if self.head is None :
return '链表为空'
elif index > self.len():
return '链表超出长度'
else:
count = 1
current = self.head
while True:
if index != count:
current = current.next
count += 1
else:
return current.data
# 仿pop：获取链表尾部的值，并删除该尾部的节点
def pop(self):
if self.head is None:
return '当前链表为空'
elif self.head.next is None:
temp = self.head.data
self.head = None
return temp
else:
current = self.head
while current.next.next is not None:
current = current.next
temp2 = current.data
current.next = None
return temp2
# 逆向链表
def reverse(self):
if self.head is None or self.head.next is None:
return '链表就一个，或者没有 逆向没意义'
else:
previous = None
current = self.head
while current is not None:
# post 关键了！如果我直接修改current.next，没有了指向下一节点的引用，链表直接断咯～
post = current.next
current.next = previous
previous = current
current = post
# 把最后一个节点的头给揪出来，不然无从下手啊～
self.head = previous
# 去重
def delrepeat(self):
if self.head is None or self.len() == 1:
return
else:
# 用一个字典来储存data出现的次数
dic = {}
temp = self.head
# 先遍历一波，给所有的data 作为键 值都为0，作为初始化
while temp is not None:
dic[str(temp.data)] = 0
temp = temp.next
previous = None
current = self.head
while current is not None:
# 如果值出现过了，那么它的值就是1，删除
if dic[str(current.data)] == 1:
previous.next = current.next
# 这个很关键，删掉了之后，我的current还要继续向后延伸，因为我还要继续检查后面的
current = current.next
else:
# 第一次出现，打上标签记为1
dic[str(current.data)] += 1
previous = current
current = current.next
# 删除链表中最小的元素
def del_minimal(self):
current = self.head
min = self.head.data
while current is not None:
if current.data < min:
min = current.data
current = current.next
self.delete(min)