freeCodeCamp/curriculum/challenges/english/08-coding-interview-prep/data-structures/perform-an-intersection-on-two-sets-of-data.english.md

id	title	challengeType
587d8253367417b2b2512c6d	Perform an Intersection on Two Sets of Data	1

Description

In this exercise we are going to perform an intersection on 2 sets of data. We will create a method on our Set data structure called intersection. An intersection of sets represents all values that are common to two or more sets. This method should take another Set as an argument and return the intersection of the two sets. For example, if setA = ['a','b','c'] and setB = ['a','b','d','e'], then the intersection of setA and setB is: setA.intersection(setB) = ['a', 'b'].

Instructions

Tests

tests:
  - text: Your <code>Set</code> class should have a <code>intersection</code> method.
    testString: assert((function(){var test = new Set(); return (typeof test.intersection === 'function')})(), 'Your <code>Set</code> class should have a <code>intersection</code> method.');
  - text: The proper collection was returned
    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 intersectionSetAB = setA.intersection(setB); return (intersectionSetAB.size() === 1 && intersectionSetAB.values()[0] === 'c')})(), 'The proper collection was returned');

Challenge Seed

function Set() {
    // the var collection will hold the set
    var collection = [];
    // this method will check for the presence of an element and return true or false
    this.has = function(element) {
        return (collection.indexOf(element) !== -1);
    };
    // this method will return all the values in the set
    this.values = function() {
        return collection;
    };
   // this method will add an element to the set
    this.add = function(element) {
        if(!this.has(element)){
            collection.push(element);
            return true;
        }
        return false;
    };
    // this method will remove an element from a set
    this.remove = function(element) {
        if(this.has(element)){
           var index = collection.indexOf(element);
            collection.splice(index,1);
            return true;
        }
        return false;
    };
    // this method will return the size of the collection
    this.size = function() {
        return collection.length;
    };
    // this method will return the union of two sets
    this.union = function(otherSet) {
        var unionSet = new Set();
        var firstSet = this.values();
        var secondSet = otherSet.values();
        firstSet.forEach(function(e){
            unionSet.add(e);
        });
        secondSet.forEach(function(e){
            unionSet.add(e);
        });
        return unionSet;
    };
    // change code below this line
    // change code above this line
}

Solution

function Set() {
    // the var collection will hold the set
    var collection = [];
    // this method will check for the presence of an element and return true or false
    this.has = function(element) {
        return (collection.indexOf(element) !== -1);
    };
    // this method will return all the values in the set
    this.values = function() {
        return collection;
    };
   // this method will add an element to the set
    this.add = function(element) {
        if(!this.has(element)){
            collection.push(element);
            return true;
        }
        return false;
    };
    // this method will remove an element from a set
    this.remove = function(element) {
        if(this.has(element)){
           var index = collection.indexOf(element);
            collection.splice(index,1);
            return true;
        }
        return false;
    };
    // this method will return the size of the collection
    this.size = function() {
        return collection.length;
    };
    // this method will return the union of two sets
    this.union = function(otherSet) {
        var unionSet = new Set();
        var firstSet = this.values();
        var secondSet = otherSet.values();
        firstSet.forEach(function(e){
            unionSet.add(e);
        });
        secondSet.forEach(function(e){
            unionSet.add(e);
        });
        return unionSet;
    };
    this.intersection = function(otherSet) {
        var intersectionSet = new Set();
        var firstSet = this.values();
        firstSet.forEach(function(e) {
            if (otherSet.has(e)) {
                intersectionSet.add(e);
            }
        })
        return intersectionSet;
    }
}