count number of array items from API Json

below is my project in Vue JS and i’m using An API to view data .. my problem is: i have an API to view single data which is called building in my case, and when i try to console.log(this.Building.floors) it gives me all the array items from 0 to 21 and i want to view those numbers from 0 to 21 in a table but i couldn’t figure it out

<template>
    <b-card no-body class="bg-default shadow">
        <b-card-header class="bg-transparent border-0">
            <h3 class="mb-0 text-white">Details</h3>
        </b-card-header>

        <el-table class="table-responsive table table-dark"
                  header-row-class-name="thead-dark"
                  :data="projects">
            <el-table-column label="Project"
                             min-width="310px"
                             prop="name">
                <template v-slot="{row}">
                    <b-media no-body class="align-items-center">
                        <a href="#" class="mr-3">
                            <b-img class="avatar" rounded="circle" alt="Image placeholder" :src="row.img" />
                        </a>
                        <b-media-body>
                            <span class="font-weight-600 name mb-0 text-sm"   v-for="(building, index) in Building.floors"
              :key="index">{{Building.floors}}</span> // i wanted to get the numbers from 0 to 21 but it didn't work
                        </b-media-body>
                    </b-media>
                </template>
            </el-table-column>
            <el-table-column label="Budget"
                             prop="budget"
                             min-width="140px">
            </el-table-column>

            <el-table-column label="Status"
                             min-width="170px"
                             prop="status">
                <template v-slot="{row}">
                    <badge class="badge-dot mr-4">
                        <i :class="`bg-${row.statusType}`"></i>
                        <span class="status" :class="`text-${row.statusType}`">{{row.status}}</span>
                    </badge>
                </template>
            </el-table-column>

            <el-table-column label="Users" min-width="190px">
                <div class="avatar-group">
                    <a href="#" class="avatar avatar-sm rounded-circle" data-toggle="tooltip"
                       data-original-title="Ryan Tompson">
                        <img alt="Image placeholder" src="img/theme/team-1.jpg">
                    </a>
                    <a href="#" class="avatar avatar-sm rounded-circle" data-toggle="tooltip"
                       data-original-title="Romina Hadid">
                        <img alt="Image placeholder" src="img/theme/team-2.jpg">
                    </a>
                    <a href="#" class="avatar avatar-sm rounded-circle" data-toggle="tooltip"
                       data-original-title="Alexander Smith">
                        <img alt="Image placeholder" src="img/theme/team-3.jpg">
                    </a>
                    <a href="#" class="avatar avatar-sm rounded-circle" data-toggle="tooltip"
                       data-original-title="Jessica Doe">
                        <img alt="Image placeholder" src="img/theme/team-4.jpg">
                    </a>
                </div>
            </el-table-column>

            <el-table-column label="Completion"
                             prop="completion"
                             min-width="240px">
                <template v-slot="{row}">
                    <div class="d-flex align-items-center">
                        <span class="completion mr-2">{{row.completion}}%</span>
                        <div>
                            <base-progress :type="row.statusType" :value="row.completion"/>
                        </div>
                    </div>
                </template>
            </el-table-column>
        </el-table>

    </b-card>
</template>
<script>
  import projects from './../projects'
  import { Table, TableColumn} from 'element-ui'
  import BuildingsService from "@/services/ApiService"
  export default {
    name: 'light-table',
    components: {
      [Table.name]: Table,
      [TableColumn.name]: TableColumn
    },
    data() {
      return {
          Flats:[],
          Floors:[],
          Building:[],
      
        projects,
        currentPage: 1
      };
    },
       mounted: function(){
      
      
      BuildingsService.getOneBuilding(`${this.$route.params.id}`).then((response) => {
      this.Building = response.data.response;
     
console.log(this.Building.floors,"single");

    });



    });
    
    }
  }
</script>

enter image description here