111 lines
3.5 KiB
Markdown
111 lines
3.5 KiB
Markdown
---
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id: 587d8254367417b2b2512c6e
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title: Perform a Difference on Two Sets of Data
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challengeType: 1
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videoUrl: ''
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localeTitle: 对两组数据执行差异
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---
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## Description
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<section id="description">在本练习中，我们将对两组数据进行区分。我们将在我们的<code>Set</code>数据结构上创建一个名为<code>difference</code> 。集合的差异应比较两组并返回第一组中不存在的项目。此方法应将另一个<code>Set</code>作为参数，并返回两个集的<code>difference</code> 。例如，如果<code>setA = ['a','b','c']</code>和<code>setB = ['a','b','d','e']</code> ，则setA和setB的差异为： <code>setA.difference(setB) = ['c']</code> 。 </section>
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## Instructions
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<section id="instructions">
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: 你的<code>Set</code>类应该有一个<code>difference</code>方法。
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testString: 'assert(function(){var test = new Set(); return (typeof test.difference === "function")}, "Your <code>Set</code> class should have a <code>difference</code> method.");'
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- text: 收回了适当的收藏
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testString: 'assert(function(){var setA = new Set(); var setB = new Set(); setA.add("a"); setA.add("b"); setA.add("c"); setB.add("c"); setB.add("d"); var differenceSetAB = setA.difference(setB); return (differenceSetAB.size() === 2) && (differenceSetAB.values() === [ "a", "b" ])}, "The proper collection was returned");'
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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function Set() {
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// the var collection will hold the set
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var collection = [];
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// this method will check for the presence of an element and return true or false
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this.has = function(element) {
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return (collection.indexOf(element) !== -1);
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};
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// this method will return all the values in the set
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this.values = function() {
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return collection;
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};
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// this method will add an element to the set
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this.add = function(element) {
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if(!this.has(element)){
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collection.push(element);
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return true;
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}
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return false;
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};
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// this method will remove an element from a set
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this.remove = function(element) {
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if(this.has(element)){
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var index = collection.indexOf(element);
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collection.splice(index,1);
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return true;
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}
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return false;
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};
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// this method will return the size of the collection
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this.size = function() {
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return collection.length;
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};
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// this method will return the union of two sets
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this.union = function(otherSet) {
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var unionSet = new Set();
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var firstSet = this.values();
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var secondSet = otherSet.values();
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firstSet.forEach(function(e){
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unionSet.add(e);
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});
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secondSet.forEach(function(e){
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unionSet.add(e);
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});
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return unionSet;
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};
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// this method will return the intersection of two sets as a new set
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this.intersection = function(otherSet) {
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var intersectionSet = new Set();
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var firstSet = this.values();
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firstSet.forEach(function(e){
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if(otherSet.has(e)){
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intersectionSet.add(e);
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}
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});
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return intersectionSet;
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};
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// change code below this line
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// change code above this line
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}
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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// solution required
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```
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</section>
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