python实现基本数据结构 链表

class Node(object):
    """
    data:数据段
    next:指针段
    """
    def __init__(self, value, next=Node):
        self.value = value
        self.next = next

    def __repr__(self):
        """
        用来定义Node的字符输出
        print 为输出data
        """
        return str(self.data)

class LinkedList(object):
    def isEmpty(self):
        return self.length == 0
    def append(self, dataOrNode):
        item = Node
        if isinstance(dataOrNode, Node):
            item = dataOrNode
        else:
            item = Node(dataOrNode)
        if not self.head:
            self.head = item
            self.length += 1
        else:
            node = self.head
            while node._next:
                node = node._next
            node._next = item
            self.length += 1
    #删除一个节点之后记得要把链表长度减一
    def delete(self, index):
    #要注意删除第一个节点的情况
    #如果有空的头节点就不用这样
    #但是我不喜欢弄头节点
        if self.isEmpty():
            print("this chain table is empty.")
            return
        if index < 0 or index >= self.length:
            print("error, out of space")
            return
        if index == 0:
            self.head = self.head._next
            self.length -= 1
            return
    #prev为保存前导节点
    #node为保存当前节点
    #当j与index相等时就
    #相当于找到要删除的节点
    j = 0
    node = self.head
    prev = self.head
    while node._next and j < index:
        prev = node
        node = node._next
        j += 1
    if j == index:
        prev._next = node._next
        self.length -= 1
    def update(self, index, data):
        if self.isEmpty() or index < 0 or index >= self.length:
            print("error! out of space")
            return
        j = 0
        node = self.head
        while node._next and j < index:
            node = node._next
            j += 1
        if j == index:
            node.data = data
    def getItem(self, index):
        if self.isEmpty() or index < 0 or index >= self.length:
            print("error: out of space")
            return
        j = 0
        node = self.head
        while node._next and j < index:
            node = node._next
            j += 1
        return node.data
    def getIndex(self, data):
        j = 0
        if self.isEmpty():
            print("this chain table is empty")
            return
        node = self.head
        while node:
            if node.data == data:
                return j
            node = node._next
            j += 1
        if j == self.length:
            print("%s not found" % str(data))
            return
    def insert(self, index, dataOrNode):
        if self.isEmpty():
            print("this chain table is empty")
            return
        if index < 0 or index >= self.length:
            print("error: out of space")
            return
        item = Node
        if isinstance(dataOrNode, Node):
            item = dataOrNode
        else:
            item = Node(dataOrNode)

        if index == 0:
            item._next = self.head
            self.head = item
            self.length += 1
            return
        j = 0
        node = self.head
        prev = self.head
        while node._next and j < index:
            prev = node
            node = node._next
            j += 1
        if j == index:
            item._next = node
            prev._next = item
            self.length += 1
    def update(self, index, data):
        if self.isEmpty() or index < 0 or index >= self.length:
            print("error: out of space")
            return
        j = 0
        node = self.head
        while node._next and j < index:
            node = node._next
            j += 1
        if j == index:
            node._data = data
    def getItem(self, index):
        if self.isEmpty() or index < 0 or index >= self.length:
            print("error, out of space")
            return
        j = 0
        node = self.head
        while node._next and j < index:
            node = node._next
            j += 1
        return node.data
    def getIndex(self, data):
        j = 0
        if self.isEmpty():
            print("this chain table is empty")
            return
        node = self.head
        while node:
            if node.data == data:
                return j
            node = node._next
            j += 1
        if j == self.length:
            print("%s not found" %str(data))
            return
    def clear(self):
        self.head = Node
        self.length = 0