javascript sets code example

Example 1: array to set javascript

const myArray = [1,2,3,1,5,8,1,2,9,4];
const unique = [...new Set(myArray)]; // [1, 2, 3, 5, 8, 9, 4]

const myString = ["a","b","c","a","d","b"];
const uniqueString = [...new Set(myString)]; //["a", "b", "c", "d"]

Example 2: set js

// Use to remove duplicate elements from the array 

const numbers = [2,3,4,4,2,3,3,4,4,5,5,6,6,7,5,32,3,4,5]

//spreading numbers of the object into an array using the new operator
console.log([...new Set(numbers)]) 

// [2, 3, 4, 5, 6, 7, 32]

Example 3: python sets

# You can't create a set like this in Python
my_set = {} # ---- This is a Dictionary/Hashmap

# To create a empty set you have to use the built in method:
my_set = set() # Correct!


set_example = {1,3,2,5,3,6}
print(set_example)

# OUTPUT
# {1,3,2,5,6} ---- Sets do not contain duplicates and are unordered

Example 4: set in javascript

let mySet = new Set()

mySet.add(1)           // Set [ 1 ]
mySet.add(5)           // Set [ 1, 5 ]
mySet.add(5)           // Set [ 1, 5 ]
mySet.add('some text') // Set [ 1, 5, 'some text' ]
let o = {a: 1, b: 2}
mySet.add(o)

mySet.add({a: 1, b: 2})   // o is referencing a different object, so this is okay

mySet.has(1)              // true
mySet.has(3)              // false, since 3 has not been added to the set
mySet.has(5)              // true
mySet.has(Math.sqrt(25))  // true
mySet.has('Some Text'.toLowerCase()) // true
mySet.has(o)       // true

mySet.size         // 5

mySet.delete(5)    // removes 5 from the set
mySet.has(5)       // false, 5 has been removed

mySet.size         // 4, since we just removed one value

console.log(mySet)
// logs Set(4) [ 1, "some text", {…}, {…} ] in Firefox
// logs Set(4) { 1, "some text", {…}, {…} } in Chrome

Example 5: set in javascript

// set is used for storing unique values
const firstSet = new Set([1, 2, 3]);

firstSet.add('hi'); //adding value to set

firstSet.add(3); //this will not give any error and it will also not be added

firstSet.delete('hi');//removing value from set

console.log(firstSet.has('hi'));//checking 'hi' is in the set or not

// showing all values in the set
console.log(firstSet);
for (const entry of firstSet.values()) {
    console.log(entry);

Example 6: object set js

let nombres = [10, 45, 75, 10 ,24,45 ] ;
//let monSet = new Set(nombres) ;
let monSet = new Set() ;

monSet.add('100') ;
monSet.add('280') ; 
//monSet.delete('100');

console.log(monSet.size) ;