SwiftUI beginner here. I am trying to set the value of a variable by calling a method inside a function. Although the method is evaluating correctly, I am not able to return the value of the variable. Please see my code:     let headers: HTTPHeaders = [         "refreshtoken": refreshToken     ]     let sessionManager = Alamofire.Session.default     let request = sessionManager.request(url, method: .post, headers: headers)     var ttrr: String = "default"     request.responseJSON { (response) in         switch response.result {         case .success( _):             let json = JSON(response.value!) //SwiftyJSON             let tr = json[0]["TRCRate"].double!             ttrr = String(tr)             print("ttrr in request: \(ttrr)")         case .failure(let error):             print("API Manager Error: \(error)")         }     }     //5. Return the ready-to-use data     print("ttrr before return: \(ttrr)")     return ttrr } And here is the print output: ttrr bfore return: default ttrr in request: 0.18 Could someone kindly point to what I am doing wrong? Thanks in advance.