javascript中数组去重复方式汇总

 1 /*实现一：基于原型扩展*/
 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 /*实现二：去除重复后数组为字符串*/
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 /*实现三：去除重复后数组为数字*/
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 /*实现四：hashtable的结构记录已有的元素，这样就可以避免内层循环*/
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]