129 lines
3.7 KiB
Markdown
129 lines
3.7 KiB
Markdown
---
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id: 587d8253367417b2b2512c6c
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title: Perform a Union on Two Sets
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challengeType: 1
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---
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## Description
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<section id='description'>
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In this exercise we are going to perform a union on two sets of data. We will create a method on our <code>Set</code> data structure called <code>union</code>. This method should take another <code>Set</code> as an argument and return the <code>union</code> of the two sets, excluding any duplicate values.
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For example, if <code>setA = ['a','b','c']</code> and <code>setB = ['a','b','d','e']</code>, then the union of setA and setB is: <code>setA.union(setB) = ['a', 'b', 'c', 'd', 'e']</code>.
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</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: Your <code>Set</code> class should have a <code>union</code> method.
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testString: assert((function(){var test = new Set(); return (typeof test.union === 'function')})(), 'Your <code>Set</code> class should have a <code>union</code> method.');
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- text: The union of <code>["a", "b", "c"]</code> and <code>["c", "d"]</code> should return <code>["a", "b", "c", "d"]</code>.
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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 unionSetAB = setA.union(setB); var final = unionSetAB.values(); return (final.indexOf('a') !== -1 && final.indexOf('b') !== -1 && final.indexOf('c') !== -1 && final.indexOf('d') !== -1 && final.length === 4)})(), 'The union of <code>["a", "b", "c"]</code> and <code>["c", "d"]</code> should return <code>["a", "b", "c", "d"]</code>.');
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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 set
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this.size = function() {
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return collection.length;
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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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function Set() {
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var collection = [];
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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.values = function() {
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return collection;
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};
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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.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.size = function() {
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return collection.length;
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};
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this.union = function(anotherSet){
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const newSet = new Set();
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const addToSet = el => newSet.add(el);
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this.values().forEach(addToSet);
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anotherSet.values().forEach(addToSet);
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return newSet;
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};
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}
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```
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</section>
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