Python无序链表

类的声明：

---

节点

class node:  # 这里不用加括号，具体参数都在init函数里，这也是和函数区别的一部分，函数的升级和高级有序集合
    def __init__(self, val):
        self.data = val
        self.next = none
    
    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

链表

class unorderList:  # 只存储表头的信息
    def __init__(self):
        self.head = None  # 注意这里是大写
    
    def isEmpty(self):
        return self.head == None

    def add(self, item):  # 由于是从首向尾遍历，那么自然是向首添加元素方便
        newNode = node(item)
        newNode.setNext(self.head)
        self.head = newNode
    
    def size(self):
        count = 0
        p = self.head
        while p != None:
            count = count + 1
            p = p.getnext()
        return count
    
    def search(self, content):
        p = self.head
        found = False  # 大写！！有了found这个较为特殊的变量时，代码更加易读清晰

        while p != None and not found:
            if p.getData == content:
                found = True
            else:
                p = p.getnext()
        
        return found

    def remove(self, content):
        previous  = None
        current = self.head
        found = False
        while current != None and not found:
            if current.getData() == content:
                found = True
            else:
                previous = current
                current = current.getnext()
        if found:
            if previous == None:
                self.head = self.head.getnext()
            else:
                previous.setNext(current.getnext())

    def append(self, content):  # 在末尾加
        newNode = node(content)
        current = self.head
        previous = None
        while current != None:
            previous = current
            current = current.getnext()
        if previous != None:
            previous.setNext(newNode)  # 注意这是函数而不是参数不能用等于，而且修改对象（这里是node）的参数也只能通过方法
        else:
            current.head = newNode  # 一定要区分上面的的if

    def pop(self):  # 删掉链尾的元素
        current = self.head
        if current.getnext == None:
            print("Error: List is empty!")
        else:
            previous = None
            while current.getnext():
                previous = current
                current = current.getnext()
            previous.setNext(None)
    
    def printList(self):
        p = self.head
        while p:
            print(p.data)
            p = p.getnext()

MyList = unorderList()
MyList.add(1)
MyList.add(2)
MyList.add(3)
MyList.add(4)
MyList.pop()
MyList.append(1)  # pop和append抵消了
MyList.remove(3)
print("search answer is ", MyList.search(3))
print("MyList's size is %d" % MyList.size())
MyList.printList()