string - How to compare each letters in an array with all the letters in another array? - Swift -

i have 2 different arrays called: criptedchar , alphabet. need check first character in criptedchar (so "criptedchar[0]) , check correspondence in alphabet. exemple: criptedchar // ["d","e","c","b"] alphabet // ["a","b","c" , on] want take d criptedchar[0] , check if there's "d" in alphabet , save position of "d" in second array. need increment number inside parenthesis of criptedchar. i'll take number user. can please me? thank you!

func decript() {     var criptedtext = incriptedtext.text!   //get text uitextfield     var criptedchar = array<character>(criptedtext.characters)  //from text char & in array :d     var alfabeto: array<character> = ["a","b", "c", "d", "e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"]     var capacitycriptedchararray = criptedchar.capacity      (var = 0; < 26; i++) {         if criptedchar[0] == alfabeto[i] {             decriptedtext.text = decriptedtext.text! + "\(newlettersfromsecondviewcontroller[i])"         }     }       (var = 0; < 26; i++) {         if criptedchar[1] == alfabeto[i] {             decriptedtext.text = decriptedtext.text! + "\(newlettersfromsecondviewcontroller[i])"         }     }      (var = 0; < 26; i++) {         if criptedchar[2] == alfabeto[i] {             decriptedtext.text = decriptedtext.text! + "\(newlettersfromsecondviewcontroller[i])"         }     }    } 

this code works, it's dumb , have no control of user input

if understand question correctly, looking (explanations inline):

// start crypted text, , empty string result: let cryptedtext = "mifpyx" var decryptedtext = ""  // 2 character arrays (of equal length): let alphabet   = array("abcdefghijklmnopqrstuvwxyz".characters) let newletters = array("ghijklmnopqrstuvwxyzabcdef".characters)  // each character in input string: c in cryptedtext.characters {     // check if `c` contained in `alphabet` array:     if let index = alphabet.indexof(c) {         // yes, is, @ position `index`!         // append corresponding character second array result:         decryptedtext.append(newletters[index])     } }  print(decryptedtext) // solved 

alternatively, can create lookup-dictionary 2 arrays:

var mapping = [ character : character ]() zip(alphabet, newletters).foreach {     mapping[$0] = $1 } 

and map each character input through dictionary:

let decryptedtext = array(cryptedtext.characters         .map { mapping[$0] }         .flatmap { $0 }     ) 

(here flatmap used filter-out nils characters not present in input array.)