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Here is the complete implementation of MyMap class − Exampleclass MyMap { constructor() { this.container = {}; } display() { console.log(this.container); } hasKey(key) { return key in this.container; } put(key, value) { this.container[key] = value; } delete(key) { if (this.hasKey(key)) { delete this.container[key]; return true; } return false; } get(key) { return this.hasKey(key) ? this.container[key] : undefined; ... Read More
Hash Table is a data structure which stores data in an associative manner. In a hash table, data is stored in an array format, where each data value has its own unique index value. Access to data becomes very fast if we know the index of the desired data.Thus, it becomes a data structure in which insertion and search operations are very fast irrespective of the size of the data. Hash Table uses an array as a storage medium and uses the hash technique to generate an index where an element is to be inserted or is to be located ... Read More
A set is an abstract data type that can store certain values, without any particular order and no repeated values. It is a computer implementation of the mathematical concept of a finite set. Unlike most other collection types, rather than retrieving a specific element from a set, one typically tests a value for membership in a set.
Whenever you want to store unique elements in a container for which the order doesn't matter and you mainly want to use it to check for membership of different objects.Sets are also useful when you want to perform operations like union, intersection, a difference like you do in mathematical sets.Let's look at both how we can define our own set and use the existing one in ES6.Methods we'll implementThe ES6 set API provides some methods. We'll implement these methods in our implementation and also look at how to use them using the built-in class.add() − Adds a new element to the ... Read More
Let's create a MySet class so that it doesn't hide the actual set class in JS. We'll create a container object that'll keep track of all our values that we add to the set. We'll also create a display function that prints the set for us. Exampleclass MySet { constructor() { this.container = {}; } display() { console.log(this.container); } }In ES6, you can directly create a set using the Set class. For example, Exampleconst set1 = new Set(); const set2 = new Set([1, 2, 5, 6]);Checking for membershipThe has method checks ... Read More
The delete method checks if a value already exists in the set, if it does, then it removes that value from the set. We can implement it as follows &minusl Exampledelete(val) { if (this.has(val)) { delete this.container[val]; return true; } return false; }You can test this using − Exampleconst testSet = new MySet(); testSet.add(1); testSet.add(2); testSet.add(5); testSet.delete(5); testSet.delete(2); testSet.display(); console.log(testSet.has(5)); console.log(testSet.has(20)); console.log(testSet.has(1));OutputThis will give the output −{ '1': 1} False False TrueIn ES6, you use the delete function as follows − Exampleconst testSet = new MySet(); testSet.add(1); testSet.add(2); testSet.add(5); testSet.delete(5); ... Read More
The clear method is pretty straightforward. We can just reassign the container variable to a new object and the set will now be empty. This can be implemented as follows − Exampleclear() { this.container = {}; }You can test this using −Exampleconst testSet = new MySet(); testSet.add(1); testSet.add(2); testSet.add(5); testSet.display(); testSet.clear(); testSet.display();OutputThis will give the output −{ '1': 1, '2': 2, '5': 5 } { }
In the set that we implemented, we can create a for each function in our class and accept a callback that we can call on every element. Let's see how we can implement such a function − ExampleforEach(callback) { for (let prop in this.container) { callback(prop); } }You can test this using − Exampleconst testSet = new MySet(); testSet.add(1); testSet.add(2); testSet.add(5); testSet.forEach(elem => console.log(`Element is ${elem}`));OutputThis will give the output −Element is 1 Element is 2 Element is 5The ES6 Set API also provides the same functionality using the forEach method.
The operation of adding 2 sets is known as a union. You need to add every object from one set to another while checking for duplicates. We can just use the 2 methods we already implemented to implement this method.We'll implement this function as a static function as we don’t want to mutate existing sets, but create and return a new one. We first need to check if the object passed to it is really an instance of the MySet class. Examplestatic union(s1, s2) { if (!s1 instanceof MySet || !s2 instanceof MySet) { console.log("The given objects ... Read More
The difference of 2 sets means the set being subtracted should have all its elements removed from the set it is being subtracted from. So we can iterate over the second set and remove all the elements present in it from the first set. Examplestatic difference(s1, s2) { if (!s1 instanceof MySet || !s2 instanceof MySet) { console.log("The given objects are not of type MySet"); return null; } let newSet = new MySet(); s1.forEach(elem => newSet.add(elem)); s2.forEach(elem => newSet.delete(elem)); return newSet; }You can test this using − Exampleconst testSet1 = ... Read More