完成自定义链表结构 1.添加数据 2.删除数据 3.修改数据 4.获得数据个数 5.通过索引获得数据 6.查询链表数据是否存在

好的，我可以帮你实现自定义链表结构。以下是链表节点的定义和链表类的实现，具体操作的实现可以根据你的需要进行修改：

# 链表节点类
class ListNode:
    def __init__(self, val):
        self.val = val
        self.next = None

# 链表类
class LinkedList:
    def __init__(self):
        self.head = None
        self.count = 0

    # 添加数据
    def add(self, val):
        new_node = ListNode(val)
        if not self.head:
            self.head = new_node
        else:
            cur_node = self.head
            while cur_node.next:
                cur_node = cur_node.next
            cur_node.next = new_node
        self.count += 1

    # 删除数据
    def remove(self, val):
        if not self.head:
            return
        if self.head.val == val:
            self.head = self.head.next
            self.count -= 1
            return
        prev_node = self.head
        cur_node = self.head.next
        while cur_node:
            if cur_node.val == val:
                prev_node.next = cur_node.next
                self.count -= 1
                return
            prev_node = cur_node
            cur_node = cur_node.next

    # 修改数据
    def modify(self, old_val, new_val):
        cur_node = self.head
        while cur_node:
            if cur_node.val == old_val:
                cur_node.val = new_val
                return True
            cur_node = cur_node.next
        return False

    # 获得数据个数
    def get_count(self):
        return self.count

    # 通过索引获得数据
    def get_val(self, index):
        if index < 0 or index >= self.count:
            return None
        cur_node = self.head
        for i in range(index):
            cur_node = cur_node.next
        return cur_node.val

    # 查询链表数据是否存在
    def search(self, val):
        cur_node = self.head
        while cur_node:
            if cur_node.val == val:
                return True
            cur_node = cur_node.next
        return False

以上就是一个简单的链表实现，你可以根据需要进行修改和扩展。