htML代码
<div id="root">
        <h2>人员列表</h2>
        <input tyPE="text" placeholder="请输入名字" v-model="keyWord">
        <ul>
            <li v-for="(p,index) of filPersons" :key="index">
                {{p.name}}-{{p.age}}-{{p.sex}}
            </li>
        </ul>
    </div>

script代码
new Vue({
        el:"#root",
        data:{
            keyWord:'',
            persons:[

                {id:'001',name:'马冬梅',age:18,sex:'女'},
                {id:'002',name:'周冬雨',age:19,sex:'女'},
                {id:'003',name:'周杰伦',age:21,sex:'男'},
                {id:'004',name:'温兆伦',age:22,sex:'男'}
        ],
        },
        computed:{
            filPersons(){
                return this.persons.filter((p)=>{//返回过滤后的数组
                    return p.name.indexOf(this.keyWord) !==-1
                })//filter是过滤函数去除了不包含关键字的情况
            }
        }
    })

html代码不变
script代码
new Vue({
        el:"#root",
        data:{
            keyWord:'',
            persons:[

                {id:'001',name:'马冬梅',age:18,sex:'女'},
                {id:'002',name:'周冬雨',age:19,sex:'女'},
                {id:'003',name:'周杰伦',age:21,sex:'男'},
                {id:'004',name:'温兆伦',age:22,sex:'男'}
        ],
        filPersons:[//如果没有此的话，persons的值改变就无法变回原来了

        ]
        
        },
        watch:{
            keyWord:{
                immediate:true,//在框的值还没变化时执行如下函数显示出所有的情况
                handler(val){
                    this.filPersons = this.persons.filter((p)=>{
                    return p.name.indexOf(val) !==-1
                })
                }
            }
            
        }
    })