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Sign Up | Log In 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 Iterating Sets // iterate over items in set // logs the items in the order: 1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2} for (let item of mySet) console.log(item) // logs the items in the order: 1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2} for (let item of mySet.keys()) console.log(item) // logs the items in the order: 1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2} for (let item of mySet.values()) console.log(item) // logs the items in the order: 1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2} // (key and value are the same here) for (let [key, value] of mySet.entries()) console.log(key) // convert Set object to an Array object, with Array.from let myArr = Array.from(mySet) // [1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2}] // the following will also work if run in an HTML document mySet.add(document.body) mySet.has(document.querySelector('body')) // true // converting between Set and Array mySet2 = new Set([1, 2, 3, 4]) mySet2.size // 4 [...mySet2] // [1, 2, 3, 4] // intersect can be simulated via let intersection = new Set([...set1].filter(x => set2.has(x))) // difference can be simulated via let difference = new Set([...set1].filter(x => !set2.has(x))) // Iterate set entries with forEach() mySet.forEach(function(value) { console.log(value) }) // 1 // 2 // 3 // 4 Implementing basic set operations function isSuperset(set, subset) { for (let elem of subset) { if (!set.has(elem)) { return false } } return true } function union(setA, setB) { let _union = new Set(setA) for (let elem of setB) { _union.add(elem) } return _union } function intersection(setA, setB) { let _intersection = new Set() for (let elem of setB) { if (setA.has(elem)) { _intersection.add(elem) } } return _intersection } function symmetricDifference(setA, setB) { let _difference = new Set(setA) for (let elem of setB) { if (_difference.has(elem)) { _difference.delete(elem) } else { _difference.add(elem) } } return _difference } function difference(setA, setB) { let _difference = new Set(setA) for (let elem of setB) { _difference.delete(elem) } return _difference } // Examples let setA = new Set([1, 2, 3, 4]) let setB = new Set([2, 3]) let setC = new Set([3, 4, 5, 6]) isSuperset(setA, setB) // => true union(setA, setC) // => Set [1, 2, 3, 4, 5, 6] intersection(setA, setC) // => Set [3, 4] symmetricDifference(setA, setC) // => Set [1, 2, 5, 6] difference(setA, setC) 413 ERROR The request could not be satisfied. Bad request. We can't connect to the server for this app or website at this time. There might be too much traffic or a configuration error. Try again later, or contact the app or website owner. If you provide content to customers through CloudFront, you can find steps to troubleshoot and help prevent this error by reviewing the CloudFront documentation. Generated by cloudfront (CloudFront) Request ID: N1n_D-bw0ErXxBV7khGCzIlacoTEiFQ1YwZArlf4l_PcRyEYcfPzpQ

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