数组之filter方法
2020-03-16 本文已影响0人
小雪洁
<!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>
