过滤数组，只保留正数，直接在原数组上操作
题目：var arr = [3,1,0,-1,-3,2,-5]
function filter(arr){
// code...
}
filter(arr)
console.log(arr) // [3,1,2]解答：var arr = [3,1,0,-1,-3,2,-5];
function filter(arr){
for(var i = 0; i< arr.length; i++){
if(arr[i] < 0){
arr.splice(i--,1); // 当前索引值截取出来
}
}
}
filter(arr);
console.log(arr); // [3,1,2]
[/i]
?过滤数组，只保留正数，原数组不变，生成新数组
题目：var arr = [3,1,0,-1,-3,2,-5]
function filter(arr){
// code...
}
var arr2 = filter(arr)
console.log(arr2) // [3,1,2]
console.log(arr) // [3,1,0,-1,-2,2,-5]解答：[i]var arr = [3,1,0,-1,-3,2,-5]
function filter(arr){
var newArr = ;
for (var i = 0; i < arr.length; i++) {
if(arr[i] > 0){
newArr.push(arr[i]);
}
}
return newArr;
}
var arr2 = filter(arr);

console.log(arr2) // [3,1,2]
console.log(arr) // [3,1,0,-1,-2,2,-5][/i][/i][/i] 查看全部

var arr = [3,1,0,-1,-3,2,-5]

function filter(arr){

// code...

}

filter(arr)

console.log(arr) // [3,1,2]

var arr = [3,1,0,-1,-3,2,-5];

function filter(arr){

    for(var i = 0; i< arr.length; i++){

        if(arr[i] < 0){

            arr.splice(i--,1); // 当前索引值截取出来

        }

    }

}

filter(arr);

console.log(arr); // [3,1,2]

[/i]

var arr = [3,1,0,-1,-3,2,-5]

function filter(arr){

// code...

}

var arr2 = filter(arr)

console.log(arr2) // [3,1,2]

console.log(arr)  // [3,1,0,-1,-2,2,-5]

[i]var arr = [3,1,0,-1,-3,2,-5]

function filter(arr){

    var newArr = ;

    for (var i = 0; i < arr.length; i++) {

        if(arr[i] > 0){

            newArr.push(arr[i]);

        }

    }

    return newArr;

}

var arr2 = filter(arr);



console.log(arr2) // [3,1,2]

console.log(arr)  // [3,1,0,-1,-2,2,-5][/i][/i][/i]