需要设计一个单链表结构，该链表结构数据域存储整数。 编写函数实现基本运算方法。基本运算方法应包括创建链表、销毁链表、求链表长度、 求链表某一位置节点的值、查找值为 x 的节点所在位置、新增节点、插入节点、删除节点。

为了设计一个单链表结构，你需要首先定义一个Node类，它包含两个属性：一个整数值和一个指向下一个节点的引用。然后你可以定义一个LinkedList类，包含链表的操作方法：

class Node:
    def __init__(self, value):
        self.value = value
        self.next = None

class LinkedList:
    def __init__(self):
        self.head = None
        self.length = 0

    # 创建链表
    def create_list(self):
        self.head = None

    # 销毁链表
    def destroy_list(self):
        self.head = None
        self.length = 0

    # 求链表长度
    def get_length(self):
        current = self.head
        while current is not None:
            self.length += 1
            current = current.next
        return self.length

    # 获取某位置节点的值
    def get_node_value(self, position):
        if position < 0 or position >= self.length:
            raise IndexError("Position out of range")
        current = self.head
        for _ in range(position):
            current = current.next
        return current.value

    # 查找值为x的节点
    def find_node_by_value(self, x):
        current = self.head
        position = 0
        while current is not None:
            if current.value == x:
                return position
            current = current.next
            position += 1
        return -1  # 如果未找到，返回-1

    # 新增节点
    def add_node(self, value):
        new_node = Node(value)
        if not self.head:
            self.head = new_node
        else:
            current = self.head
            while current.next:
                current = current.next
            current.next = new_node
        self.length += 1

    # 插入节点
    def insert_node(self, position, value):
        if position < 0 or position > self.length:
            raise IndexError("Invalid position")
        new_node = Node(value)
        if position == 0:
            new_node.next = self.head
            self.head = new_node
        else:
            current = self.head
            for _ in range(position - 1):
                current = current.next
            new_node.next = current.next
            current.next = new_node
        self.length += 1

    # 删除节点
    def delete_node(self, position):
        if position < 0 or position >= self.length:
            raise IndexError("Invalid position")
        if position == 0:
            self.head = self.head.next
        else:
            current = self.head
            for _ in range(position - 1):
                current = current.next
            current.next = current.next.next
        if self.head is None:
            self.length = 0
        else:
            self.length -= 1