数组之filter方法

作者: 小雪洁 | 来源:发表于2020-03-16 13:58 被阅读0次

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title>filter过滤元素</title>
    </head>
    <body>
    </body>
    <script>
        let arr=["hxj","ydc","hwx"];
        //arr.filter(function(item,index,arr){})
        //遍历数组内所有元素，满足函数内条件的返回该元素，
        let newArr=arr.filter(function(item,index,arr){
            //return true;//newArr=["hxj", "ydc", "hwx"];
            return false;//newArr=[];
        });
        console.log(newArr);
        const users=[
            {name:"hxj",age:30},
            {name:"ydc",age:28},
            {name:"hwx",age:34},
        ];
        let newUser=users.filter(function(item){
            return item.age>=30;
        });
        console.log(newUser);//[{name:"hxj",age:30},{name: "hwx", age: 34}]
    
        //自定义一个过滤函数
        let a=[1,2,3,4,5];
        function filter(arr,callback){
            let newarr=[];
            for(let value of arr){
                callback(value)==true?newarr.push(value):"";
            }
            return newarr;
        }
        console.log(filter(a,function(item){
            return item>2;
        }));//[3, 4, 5]
    </script>
</html>