两种简单的数组去重

1.利用splice直接改变原数组

  /**题目
    条件 [arr1,arr2] = [[1,1,1,2,2,3,4,5,5],[2,3,3,4,4,5,6,7,8,8,]];
    
    结果  arr = [1,2,3,4,5,6,7,8];
    */
    [arr1,arr2] = [[1,1,1,2,2,3,4,5,5],[2,3,3,4,4,5,6,7,8,8,]];
    
    let arr = arr1.concat(arr2);
    arr.sort();
    for(var i = 0; i < arr.length; i++){
      if(arr[i] == arr[i + 1]){
        arr.splice(i,1);
        i--;
      }
    }
    console.log(arr);

 2.利用对象的属性名不会重复

    [arr1,arr2] = [[1,1,1,2,2,3,4,5,5],[2,3,3,4,4,5,6,7,8,8,]];
    var newArr = arr1.concat(arr2);
    var obj = {};
    var arr =[];
    for(var i = 0; i < newArr.length; i++) {
      if(!obj[newArr[i]]) {
        obj[newArr[i]] = '123';　　//读取对象 和  写入对象  字符串的时候 都要用   []
        arr.push(newArr[i]);
      }
    }
    console.log(arr);