string - Get rid of these Optional values -

using xcode 7 beta, swift 2.0

i'm saving , loading credentials keychain, somehow when loading "optional(value)" back, looks part of string displayed in textbox or when sending api

this how save , load credentials now, see i've done lot of nil checking make sure not nil or optional, indeed overuse of explanation marks...

func savecredentials(credentials : [string : string!]!) -> bool {     if(credentials.count == 2)     {         //only proceed when have 2 keys:  username , password         let username = credentials["username"]         let password = credentials["password"]          if let usernamestr = username         {//also tried username!=nil && password != nil             if let passwordstr = password             { //usernamestr , passwordstr of type string!                 let nsdatausername = usernamestr!.datausingencoding(nsutf8stringencoding)                 let nsdatapassword = passwordstr!.datausingencoding(nsutf8stringencoding)                 if(nsdatausername != nil && nsdatapassword != nil)                 {                     localstorage.savetokeychain("username", data: nsdatausername!)                     localstorage.savetokeychain("password", data: nsdatapassword!)                     return true                 }             }          }     }     return false }  func loadcredentials() -> [string : string!]? {     let nsdatausername = localstorage.loadfromkeychain("username")     let nsdatapassword = localstorage.loadfromkeychain("password")     if(nsdatausername != nil && nsdatapassword != nil)     {         let username : string! = string(nsstring(data: nsdatausername!, encoding: nsutf8stringencoding))         let password : string! = string(nsstring(data: nsdatapassword!, encoding: nsutf8stringencoding))         if let usernamestr = username         {             if let passwordstr = password             { // password of type string!, passwordstr of type string                 var credentials : [string: string!] = [string : string]()                 credentials["username"] = usernamestr                 credentials["password"] = passwordstr                 return credentials             }         }     }     return nil } 

and when send api, method requires non-optional string. method work when logging in, getting strings text fields, not filter out optional when coming keychain.

func loginuser(email : string!, password : string!) {     print("loginuser(email : \(email), password: \(password))")     var parameters = [string : anyobject]()     parameters["username"] = email     parameters["password"] = password    ...... 

the strings send savecredentials method, same user logged in with:

func loginlocalaccount(email : string!, password : string!) {     databaseapi.loginuser(email!, password: password!) //login goes fine     savecredentials(email!, password: password!) //manages optional in it.. } 

i suspect has saving , loading keychain, interests, this use save , load keychain.

i want rid of them because when app starts, loads credentials , tries login @ api. ofcourse error username not valid e-mail, because optional(email@adress.com)

you're overusing !. don't need them. try learn more implicitly unwrapped optionals, optionals, ... code mess (no offense, everybody's learning).

back optional problem, it's caused line:

let username : string! = string(nsstring(data: nsdatausername!, encoding: nsutf8stringencoding)) 

convenience init?(data: nsdata, encoding: uint) - inner part utilizes failable initializer, so, nsstring? result. initialization of string optional nsstring? produces optional well. but, has no sense @ in way.

first part - remove optional

utilizing new guard:

guard let loadedpassword = nsstring(data: passworddata, encoding: nsutf8stringencoding) else {   fatalerror("ooops") } 

loadedpassword contains nsstring (not nsstring?) now.

second part - nsstring -> string

you did read (if not, read) strings , characters bridging, ... if can freely exchange nsstring string, can think you're done:

var dict = [string:string]() dict["password"] = loadedpassword 

nope. produces following error:

nsstring not implicitly convertible string; did mean use 'as' explicitly convert?

slight change , you're done:

var dict = [string:string]() dict["password"] = loadedpassword string 

complete example

let password = "hallo" guard let passworddata = password.datausingencoding(nsutf8stringencoding) else {   fatalerror("ooops") }  // save/load to/from keychain  guard let loadedpassword = nsstring(data: passworddata, encoding: nsutf8stringencoding) else {   fatalerror("ooops") }  var dict = [string:string]() dict["password"] = loadedpassword string  print(dict) // "[password: hallo]\n"