python 无序列表 单链表

class Node():
    def __init__(self,Data):
        self.data = Data  # 当前节点
        self.next = None  # 下一节点，为None表示没有下一个节点
    
    def getData(self):
        return self.data
    
    def getNext(self):
        return self.next
    
    def setData(self,newData):
        self.data = newData

    def setNext(self,newNext):
        self.next = newNext

class UnorderedList():
    def __init__(self):
        self.head = None
    
    def isEmpty(self):
        return self.head == None
        
    def add(self,item):
        temp = Node(item)         # 创建一个节点
        temp.setNext(self.head)   # 将当前的头节点变成新创建的节点的下一个节点：即往后移动一位
        self.head = temp          # 再将新创建的节点设成头
    
    def size(self):
        current = self.head
        count = 0
        while current != None:
            count += 1
            current = current.getNext()
        return count
        
    def search(self,item):
        current = self.head
        while current != None:
            if current.getData() == item:
                return True
            else:
                current = current.getNext()
        return False
    
    def remove(self,item):
        if self.search(item) == True:
            current = self.head
            previous = None
            found = False
            while not found:
                if current.getData() == item:
                    found = True
                else:
                    previous = current
                    current = current.getNext()
            if previous == None:
                self.head = current.getNext()
            else:
                previous.setNext(current.getNext())
        else:
            print('No item found')
            


li = UnorderedList()
li.add(5)
li.add(6)
li.add(7)
print(li.size())
print(li.search(6))
li.remove(6)
print(li.search(5))