To delete the selected cycle id

del (whether the item) {

      this.diseaseName.splice(num, 1);

    },

     <el-col>

            <El-form-item label = "related diseases" prop = "disease">

              <el-select

                v-model="formDatanew.disease"

                value-key="id"

                placeholder = "Please select the relevant disease"

                @change="currentSel"

              >

                <el-option

                  v-for="item in diseaseList"

                  :key="item.id"

                  :label="item.name"

                  :value="item"

                ></el-option>

              </el-select>

              <span

                class="diseaseStyle"

                v-for="(item, index) in diseaseName"

                :key="index"

                @click="del(index,item)"

              >{{item}}X</span>

            </el-form-item>

          </el-col>