Append String in Swift

In Swift, appending strings is as easy as:

let stringA = "this is a string"
let stringB = "this is also a string"
let stringC = stringA + stringB

Or you can use string interpolation.

let stringC = "\(stringA) \(stringB)"

Notice there will now be whitespace between them.

Note: I see the other answers are using var a lot. The strings aren't changing and therefore should be declared using let. I know this is a small exercise, but it's good to get into the habit of best practices. Especially because that's a big feature of Swift.

let string2 = " there"
var instruction = "look over"

choice 1 :

 instruction += string2;

  println(instruction)

choice 2:

 var Str = instruction + string2;

 println(Str)

ref this

Add this extension somewhere:

extension String {
    mutating func addString(str: String) {
        self = self + str
    }
}

Then you can call it like:

var str1 = "hi"
var str2 = " my name is"
str1.addString(str2)
println(str1) //hi my name is

A lot of good Swift extensions like this are in my repo here, check them out: https://github.com/goktugyil/EZSwiftExtensions

You can simply append string like:

var worldArg = "world is good"

worldArg += " to live";

var string1 = "This is ";
var string2 = "Swift Language";
var appendString = string1 + string2;
println("APPEND STRING: \(appendString)");

According to Swift 4 Documentation, String values can be added together (or concatenated) with the addition operator (+) to create a new String value:

let string1 = "hello"
let string2 = " there"
var welcome = string1 + string2
// welcome now equals "hello there"

You can also append a String value to an existing String variable with the addition assignment operator (+=):

var instruction = "look over"
instruction += string2
// instruction now equals "look over there"

You can append a Character value to a String variable with the String type’s append() method:

let exclamationMark: Character = "!"
welcome.append(exclamationMark)
// welcome now equals "hello there!"

> Swift2.x:

String("hello ").stringByAppendingString("world") // hello world

Strings concatenate in Swift language.

let string1 = "one"

let string2 = "two"

var concate = " (string1) (string2)"

playgroud output is "one two"

In the accepted answer PREMKUMAR there are a couple of errors in his Complete code in Swift answer. First print should read (appendString) and Second print should read (appendString1). Also, updated println deprecated in Swift 2.0

His

let string1 = "This is"
let string2 = "Swift Language"
var appendString = "\(string1) \(string2)"
var appendString1 = string1+string2
println("APPEND STRING1:\(appendString1)")
println("APPEND STRING2:\(appendString2)")

Corrected

let string1 = "This is"
let string2 = "Swift Language"
var appendString = "\(string1) \(string2)"
var appendString1 = string1+string2
print("APPEND STRING:\(appendString)")
print("APPEND STRING1:\(appendString1)")

SWIFT 2.x

let extendedURLString = urlString.stringByAppendingString("&requireslogin=true")

SWIFT 3.0

From Documentation: "You can append a Character value to a String variable with the String type’s append() method:" so we cannot use append for Strings.

urlString += "&requireslogin=true"

"+" Operator works in both versions

let extendedURLString = urlString+"&requireslogin=true"

let firstname = "paresh"
let lastname = "hirpara"
let itsme = "\(firstname) \(lastname)"