JS基础算法之-数组去重

先定义一个数组

let arr = [1,2,3,3,4,5,5,6,9,6,7,8,9,4,9];

1、

removeRepetitionItem = (arr) =>{
    for(let i=0; i<arr.length+1; i++){
        for(let j=i+1; j<arr.length; j++){
            if(arr[i] == arr[j]){
                arr.splice(j,1);
                j--;
            }
        }
    }
    return arr;
}

let arr2 = removeRepetitionItem(arr);
console.log(arr2);//[1,2,3,4,5,6,7,8,9]

2、

re = (arr) =>{
    for(let i=0; i< arr.length;i++){
        if(arr.indexOf(arr[i]) != i){
            arr.splice(i,1);
            i--;
        }
    }
    return arr;
}
let arr2 = re(arr);
console.log(arr2);//[1,2,3,4,5,6,7,8,9]