How to use the Swift Set collection

This article will explain in detail how to use the Swift Set collection. The editor thinks it is very practical, so I share it for you as a reference. I hope you can get something after reading this article.

1. Create Set collection / / create Setvar set: Set = [1,2,3] var set2 = Set (arrayLiteral: 1,2,3) 2. Get the element / / set get the minimum value set.min () / / get the first element, indefinite set [set.startIndex] set.first// gets the element through the subscript and can only move backward, not forward / / get the second element set.index (after: set.startIndex) / / get several elements after a subscript [set.index (set.startIndex, offsetBy: 2)] 3. Common method / / get the number of elements set.count// judge empty set if set.isEmpty {print ("set is empty")} / / determine whether the collection contains an element if (set.contains (3)) {print ("set contains 3")} / / insert set.insert (0) / / remove set.remove (2) set.removeFirst () / / remove the element at the specified location. Unpack, get the Optional type, if you remove the element that does not exist EXC_BAD_INSTRUCTIONset.remove (at: set.firstIndex (of: 1)!) set.removeAll () var setStr1: Set = ["1", "2", "3", "4"] var setStr2: Set = ["1", "2", "5", "6"] / / Set take intersection setStr1.intersection (setStr2) / / {"2", "1"} / / Set take intersection setStr1.symmetricDifference (setStr2) / / {"4", "5" "3", "6"} / / Set merge setStr1.union (setStr2) / / {"2", "3", "1", "4", "6", "5"} / / Set take relative complement (difference) A.subtract (B), that is, the set of elements that belongs to A but does not belong to B setStr1.subtract (setStr2) / / {"3", "4"} var eqSet1: Set = [1,2,3] var eqSet2: Set = [3,1,2] / / judge that the Set set is equal if eqSet1 = = eqSet2 {print ("the two sets are equal only when all the elements in the set are equal Independent of the order of elements ")} let set3: Set = [0,1] let set4: Set = [0,1,2] / / judgment subset set3.isSubset (of: set4) / / set3 is a subset of set4, trueset3.isStrictSubset (of: set4) / / set3 is a true subset of set4, true// determines that set4.isSuperset (of: set3) / / set4 is a superset of set3, trueset4.isStrictSuperset (of: set3) / / set4 is a true superset of set3. Set traversal / / traversal element for ele in set4 {print (ele)} / / Enum of the traversal collection for ele in set4.enumerated () {print (index)} / / subscript traverses for index in set4.indices {print (set 4 [index])} / / sort from smallest to largest, and then traverse for ele in set4.sorted (by: