How To Filter Array Using Element in Another Array in Swift?

Use Set Operations

Set(toBeFiltered).intersection(Set(theFilter))

Read more: https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/CollectionTypes.html

let toBeFiltered = ["star0", "star2", "star1", "star0", "star3", "star4"]let theFilter = ["star1", "star3"]let filtered = toBeFiltered.filter(theFilter.contains)

You can also filter Struct array as well

struct myStruct        {          var userid:String;          var details:String;          init() {            userid = "default value";            details = "default";          }    };    var f1 = myStruct();    f1.userid = "1";    f1.details = "Good boy";    var f2 = myStruct();    f2.userid = "2";    f2.details = "Bad boy";    var f3 = myStruct();    f3.userid = "3";    f3.details = "Gentleman";    var arrNames1:Array = [f1,f3];    var arrNames2:Array = [f3,f1,f2];    let filteredArrayStruct =  arrNames1.filter( { (user: myStruct) -> Bool in      return arrNames2.contains({ (user1: myStruct) -> Bool in        return user.userid == user1.userid;      })    })print(filteredArrayStruct)

For Set you must conforms the Hashable protocol

class mytestclass: Hashable{  var userid:Int ;  var details:String;  var hashValue: Int {    return self.userid  }  init(userid: Int, details:String) {  self.userid = userid;  self.details = details;  }}func ==(lhs: mytestclass, rhs: mytestclass) -> Bool {  return lhs.userid == rhs.userid}var t1 = mytestclass(userid: 1,details: "Good boy");var t2 = mytestclass(userid: 2,details: "bad boy");var t3 = mytestclass(userid: 3,details: "gentle man");var classArrayNames:Set<mytestclass> = [t1,t2];var classArrayNames2:Set<mytestclass> = [t3,t1,t2]; let result =  Set(classArrayNames).intersect(classArrayNames2)