js数组去重的方法总结

// 最简单数组去重法/** 新建一新数组，遍历传入数组，值不在新数组就push进该新数组中* IE8以下不支持数组的indexOf方法*/function uniq(array){  var temp = []; //一个新的临时数组  for(var i = 0; i < array.length; i++){    if(temp.indexOf(array[i]) == -1){      temp.push(array[i]);    }  }  return temp;}var newArray = [1,2,2,4,9,6,7,5,2,3,5,6,5];console.log(uniq(newArray));// [1, 2, 4, 9, 6, 7, 5, 3]/*var newArray = ['mu','zi','dig','big','z','mu','zi','muzidigbig']console.log(uniq(newArray));//["mu", "zi", "dig", "big", "z", "muzidigbig"]*/

/** 还是得调用“indexOf”性能跟方法1差不多，* 实现思路：如果当前数组的第i项在当前数组中第一次出现的位置不是i，* 那么表示第i项是重复的，忽略掉。否则存入结果数组。*/function uniq(array){  var temp = [];  for(var i = 0; i < array.length; i++) {    //如果当前数组的第i项在当前数组中第一次出现的位置是i，才存入数组；否则代表是重复的    if(array.indexOf(array[i]) == i){      temp.push(array[i])    }  }  return temp;}var aa = [1,2,"2",4,9,"a","a",2,3,5,6,5];console.log(uniq(aa));//[1, 2, "2", 4, 9, "a", 3, 5, 6]

/** 给传入数组排序，排序后相同值相邻，* 然后遍历时,新数组只加入不与前一值重复的值。* 会打乱原来数组的顺序*/function uniq(array){  array.sort();  console.log(array.sort());  var temp=[array[0]];  for(var i = 1; i < array.length; i++){    if( array[i] !== temp[temp.length-1]){      temp.push(array[i]);    }  }  return temp;}var aa = [1,2,"2",4,9,"a","a",2,3,5,6,5];console.log(uniq(aa));//[1, "2", 2, 3, 4, 5, 6, 9, "a"]

// 思路：获取没重复的最右一值放入新数组/** 推荐的方法* 方法的实现代码相当酷炫，* 实现思路：获取没重复的最右一值放入新数组。* （检测到有重复值时终止当前循环同时进入顶层循环的下一轮判断）*/function uniq(array){  var temp = [];  var index = [];  var l = array.length;  for(var i = 0; i < l; i++) {    for(var j = i + 1; j < l; j++){      if (array[i] === array[j]){        i++;        j = i;      }    }    temp.push(array[i]);    index.push(i);  }  console.log(index);//[0, 2, 5, 6, 7, 8, 9]  return temp;}var aa = [1,2,2,3,5,3,6,5,'3','muzi'];console.log(uniq(aa));// [1, 2, 3, 6, 5, "3", "muzi"]

//利用数组原型对象上的includes方法function unique(arr){ var bArr= []; for(var i=0; i<arr.length; i++){  if( !bArr.includes(arr[i]) ){ // 如果bArr新数组包含当前循环item   bArr.push(arr[i]);  } } return bArr;}var aa = [1,2,2,3,5,3,6,5,'3','muzi'];console.log(unique(aa))//[1, 2, 3, 5, 6, "3", "muzi"]

//利用数组原型对象上的filter和includes方法function unique6(arr){ var bArr= []; bArr= arr.filter(function(item){ return bArr.includes(item) ? null : bArr.push(item); }); return bArr;}var aa = [1,2,2,3,5,3,6,5,'3','muzi'];console.log(unique6(aa))//[1, 2, 3, 5, 6, "3", "muzi"]

//利用数组原型对象上的forEach和includes方法function unique7(arr){ var bArr= []; arr.forEach(function(item){  bArr.includes(item) ? null : bArr.push(item); });  return bArr;}var aa = [1,2,2,3,5,3,6,5,'3','muzi'];console.log(unique7(aa))//[1, 2, 3, 5, 6, "3", "muzi"]

  Array.prototype.method1 = function(){    var arr=[];  //定义一个临时数组    for(var i = 0; i < this.length; i++){  //循环遍历当前数组      //判断当前数组下标为i的元素是否已经保存到临时数组      //如果已保存，则跳过，否则将此元素保存到临时数组中      if(arr.indexOf(this[i]) == -1){        arr.push(this[i]);      }    }    return arr;  };  var arrNum1 = [1,4,1,1,3,3,4,6,7,8,3,7,0,2,11,2,'muzi','digbig','muzi'];  console.log(arrNum1.method1());//[1, 4, 3, 6, 7, 8, 0, 2, 11, "muzi", "digbig"]

  let arr = [1,2,2,3,4,4,4];  let s = new Set(arr);  //结果：Set {1,2,3,4}  let newArr = Array.from(s);  //结果：[1,2,3,4],完成去重