javascript中數組去重複方式匯總

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JavaScript中關於數組去重複的方式很多，下面匯總了常見的幾種實現方式。

 1 /*實現一：基於原型擴充*/ 2 Array.prototype.removeDuplicate = function() { 3     var arrObj = {}, 4         newArr = [], 5         len = this.length; 6     for(var i = 0; i < len; i++) { 7         var value = this[i], 8             type = (typeof value) + value; 9         if(arrObj[type] === undefined) {10             newArr.push(value);11             arrObj[type] = len;12         }13     }14     return newArr;15 }16 17 var s = [1, 1, 2, 3, 4, 5, 4, 3, 4, 4, 5, 5, 6, 7];18 s.removeDuplicate(); //[1, 2, 3, 4, 5, 6, 7]19 20 /*實現二：去除重複後數組為字串*/21 var removeDuplicate = function(array) {22     array = array || [];23     var arrObj = {},24         len = array.length;25     for(var i = 0; i < len; i++) {26         var data = array[i];27         if(typeof(arrObj[data]) === ‘undefined‘) {28             arrObj[data] = 1;29         }30     }31     array.length = 0;32     for(var arr in arrObj) {33         array[array.length] = arr;34     }35     return array;36 }37 38 var s = [1, 1, 2, 3, 4, 5, 4, 3, 4, 4, 5, 5, 6, 7];39 removeDuplicate(s); //["1", "2", "3", "4", "5", "6", "7"]40 41 /*實現三：去除重複後數組為數字*/42 var removeDuplicate = function(array) {43     var str = [];44     for(var i = 0, len = array.length; i < len; i++) {45         !RegExp(array[i], ‘g‘).test(str.join(‘,‘)) && (str.push(array[i]));46     }47     return str;48 }49 50 var s = [1, 1, 2, 3, 4, 5, 4, 3, 4, 4, 5, 5, 6, 7];51 removeDuplicate(s); //[1, 2, 3, 4, 5, 6, 7]52 53 /*實現四：hashtable的結構記錄已有的元素，這樣就可以避免內層迴圈*/54 var removeDuplicate = function(array) {55     var hash = {},56         newArr = [];57     for(var i = 0, elem; (elem = array[i]) != null; i++) {58         if(!hash[elem]) {59             newArr.push(elem);60             hash[elem] = true;61         }62     }63     return newArr;64 }65 66 var s = [1, 1, 2, 3, 4, 5, 4, 3, 4, 4, 5, 5, 6, 7];67 removeDuplicate(s); //[1, 2, 3, 4, 5, 6, 7]

上面四種實現方式中，都實現了數組去重複的需求，但在實現方式和效能上面存在一定的差異，其中實現四的方式效率最高。

javascript中數組去重複方式匯總