v-for循环渲染列表时，怎么直接把从对象取出的值赋值给class属性

<v-touch v-for="(plan,index) in plans" v-on:swipeleft="onSwipeLeft(index)" v-on:swiperight="onSwipeRight(index)" v-on:tap="onTap()" class="task">
<span class="glyphicon" :class="[plan.sta,plan.pri]"></span>
<div class="content">
{{plan.content}}
</div>
<div class="right" :class="{ractive:i==index}">
<div class="op-edit" ><router-link :to="{ name: 'update', params: { taskId: index }}">编辑</router-link></div>
<div class="op-del" @click="deletePlan(index)">删除</div>
</div>
<div class="left" :class="{lactive:j==index}">
<div class="op-1" @click="updateSta3(index)">已完成</div>
<div class="op-2" @click="updateSta2(index)">待办</div>
<div class="op-3" @click="updateSta1(index)">进行中</div>
</div>
</v-touch>