VUE component has data and does not render v-for

code show as below:

<!--
 * @Author: your name
 * @Date: 2020-09-16 10:32:50
 * @LastEditTime: 2020-09-17 12:37:31
 * @LastEditors: qal
 * @Description: In User Settings Edit
 * @FilePath: \mt-app\src\components\changeCity\category.vue
-->
<template>
  <div class="categroy">
    <dl class="m-categroy">
      <dt>按拼音首字母选择:</dt>
      <dd v-for="(item,index) in list" :key="index">
        <a :href="'#city-'+item ">{
  
   
   {item}}</a>
      </dd>
    </dl>
    <dl class="m-categroy-section" v-for="(item,index) in cityObj" :key="'city-'+index" :id="'city-'+index">
      <dt>{
  
   
   {index}}</dt>
      <dd>
        <span v-for="x  in item" :key="x.id" @click="chan