集合的实现3--ES6的set类型

ES6也实现了Set类型。

ES6入门之set和map

我们看到

var set = new Set([1, 2, 2, 3, 3]);console.log(set);

我们也可以稍微修改一下程序。使之可以接受参数。

看下面的注释部分。由于使用的是函数表达式（对应的是函数声明）。因此代码得放在合理的位置

/*使用数组来模拟集合*/function Set(arr) {var items = [];this.add = function (value) {if(this.has(value)) {return false;}items.push(value);return true;}this.has = function (value) {if(items.indexOf(value) == -1) {return false;}return true;}/*添加一些Set初始化的代码*/if(arr) {for(var i=0; i<arr.length; ++i) {this.add(arr[i])}}this.remove = function (value) {if(this.has(value)) {var index = items.indexOf(value);items.splice(index, 1);return true;}return false;}this.clear = function () {items = [];}this.size = function () {return items.length;}this.values = function () {return items;}this.print = function () {console.log(items);}this.union = function (other_set) {var new_set = new Set();var values = this.values();for(var i=0; i<values.length; ++i) {new_set.add(values[i]);}values = other_set.values();for(var i=0; i<values.length; ++i) {if(!new_set.has(values[i])) {new_set.add(values[i]);}}return new_set;}this.intersection = function (other_set) {var new_set = new Set();var values = this.values();for(var i=0; i<values.length; ++i) {if(other_set.has(values[i])) {new_set.add(values[i]);}}return new_set;}this.difference = function (other_set) {var new_set = new Set();var values = this.values();for(var i=0; i<values.length; ++i) {if(!other_set.has(values[i])) {new_set.add(values[i]);}}return new_set;}this.isSubset = function (other_set) {var flag = true;var values = other_set.values();for(var i=0; i<values.length; ++i) {if(!this.has(values[i])) {return false;}}return true;}}var set = new Set([1, 2, 2, 1, 3]);set.print();