需求：

根据每个用户的提交次数、撤回次数，动态计算出实际次数，并且提交次数不能小于撤回次数

<template>
  <div>
    <el-table
      :data="tableData"
      style="width: 80%"
      border>
      <el-table-column
        prop="date"
        label="日期"
        width="120">
      </el-table-column>
      <el-table-column
        prop="name"
        label="姓名"
        width="120">
      </el-table-column>
      <el-table-column
        prop="address"
        label="地址"
        width="250">
      </el-table-column>
      <el-table-column
        prop="submitNumber"
        label="提交次数"
        width="180">
        <template slot-scope="scope">
          <el-input-number v-model="scope.row.submitNumber" size="small" :min="scope.row.withdrawNumber" label="描述文字" @change="(currentValue)=>setProNum(currentValue,scope.$index)"></el-input-number>
        </template>
      </el-table-column>
      <el-table-column
        prop="withdrawNumber"
        label="撤回次数">
      </el-table-column>
      <el-table-column
        prop="actualNumber"
        label="实际次数">
      </el-table-column>
    </el-table>
  </div>
</template>

<script>
export default {
  name: 'TableRowIndex',
  data() {
    return {
      tableData: [{
        date: '2016-05-02',
        name: '王小虎',
        address: '上海市普陀区金沙江路 1518 弄',
        submitNumber:34,
        withdrawNumber:2,
        actualNumber:32,
      }, {
        date: '2016-05-04',
        name: '王小虎',
        address: '上海市普陀区金沙江路 1517 弄',
        submitNumber:6,
        withdrawNumber:3,
        actualNumber:3,
      }, {
        date: '2016-05-01',
        name: '王小虎',
        address: '上海市普陀区金沙江路 1519 弄',
        submitNumber:13,
        withdrawNumber:7,
        actualNumber:6,
      }, {
        date: '2016-05-03',
        name: '王小虎',
        address: '上海市普陀区金沙江路 1516 弄',
        submitNumber:34,
        withdrawNumber:12,
        actualNumber:22,
      }]
    };
  },
  methods: {
    setProNum(currentValue, index){
      this.tableData[index].actualNumber = currentValue - this.tableData[index].withdrawNumber
    },
  },
};
</script>