js数组去重的方法汇总_javascript技巧

//传入数组 function unique1(arr){ var tmpArr = []; for(var i=0; i
         

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function unique2(arr){ var tmpArr = []; //结果数组 for(var i=0; i
         

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function unique3(arr){ var tmpArr = [], hash = {};//hash为hash表 for(var i=0;i
         

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Array.prototype.unique1 = function (){ var tmpArr = []; for (var i = 0; i < this.length; i++){ if (tmpArr.indexOf(this[i]) == -1){ tmpArr.push(this[i]); } } return tmpArr; } Array.prototype.unique2 = function(){ var tmpArr = []; //结果数组 for(var i = 0; i < this.length; i++){ if (this.indexOf(this[i]) == i){ tmpArr.push(this[i]); } } return tmpArr; } Array.prototype.unique3 = function(){ var tmpArr=[], hash = {}; for(var i = 0; i < this.length; i++){ if (!hash[this[i]]){ hash[this[i]] = true; tmpArr.push(this[i]); } } return tmpArr; }

var s = new Set([1, 2, 3,]); s; // Set {1, 2, 3}

>>> s.add(4) >>> s {1, 2, 3, 4} >>> s.add(4) >>> s {1, 2, 3, 4}//重复元素不会被添加

s; // Set {1, 2, 3, 4} s.delete(3); s; // Set {1, 2, 4}

var s = new Set(['A', 'B', 'C']); for (var x of s) { // 遍历Set alert(x); }

var s = new Set(['A', 'B', 'C']); s.forEach(function (element, set) { alert(element); });