How do I concatenate strings in Swift?

Question

How to concatenate string in Swift?

In Objective-C we do like

NSString *string = @"Swift";
NSString *resultStr = [string stringByAppendingString:@" is a new Programming Language"];

or

NSString *resultStr=[NSString stringWithFormat:@"%@ is a new Programming Language",string];

But I want to do this in Swift-language.

Answer 1

You can concatenate strings a number of ways:

let a = "Hello"
let b = "World"

let first = a + ", " + b
let second = "\(a), \(b)"

You could also do:

var c = "Hello"
c += ", World"

I'm sure there are more ways too.

Bit of description

let creates a constant. (sort of like an NSString). You can't change its value once you have set it. You can still add it to other things and create new variables though.

var creates a variable. (sort of like NSMutableString) so you can change the value of it. But this has been answered several times on Stack Overflow, (see difference between let and var).

Note

In reality let and var are very different from NSString and NSMutableString but it helps the analogy.

Answer 2

You can add a string in these ways:

• str += ""
• str = str + ""
• str = str + str2
• str = "" + ""
• str = "\(variable)"
• str = str + "\(variable)"

I think I named them all.

Answer 3

var language = "Swift" 
var resultStr = "\(language) is a new programming language"

Answer 4

This will work too:

var string = "swift"
var resultStr = string + " is a new Programming Language"

Answer 5

\ this is being used to append one string to another string.

var first = "Hi" 
var combineStr = "\(first) Start develop app for swift"

You can try this also:- + keyword.

 var first = "Hi" 
 var combineStr = "+(first) Start develop app for swift"

Try this code.

Answer 6

let the_string = "Swift"
let resultString = "\(the_string) is a new Programming Language"

Answer 7

Very Simple:

let StringA = "Hello"
let StringB = "World"
let ResultString = "\(StringA)\(StringB)"
println("Concatenated result = \(ResultString)")

Answer 8

You can now use stringByAppendingString in Swift.

var string = "Swift"
var resultString = string.stringByAppendingString(" is new Programming Language")

Answer 9

Xcode didn't accept optional strings added with a normal string. I wrote this extensions to solve that problem:

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

Then you can call it like:

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

However you could now also do something like this:

var str1: String?
var str1 = "hi"
var str2 = " my name is"
str1! += str2

Answer 10

It is called as String Interpolation. It is way of creating NEW string with CONSTANTS, VARIABLE, LITERALS and EXPRESSIONS. for examples:

      let price = 3
      let staringValue = "The price of \(price) mangoes is equal to \(price*price) "

also

let string1 = "anil"
let string2 = "gupta"
let fullName = string1 + string2  // fullName is equal to "anilgupta"
or 
let fullName = "\(string1)\(string2)" // fullName is equal to "anilgupta"

it also mean as concatenating string values.

Hope this helps you.

Answer 11

To print the combined string using

Println("\(string1)\(string2)")

or String3 stores the output of combination of 2 strings

let strin3 = "\(string1)\(string2)"

Answer 12

One can also use stringByAppendingFormat in Swift.

var finalString : NSString = NSString(string: "Hello")
finalString = finalString.stringByAppendingFormat("%@", " World")
print(finalString) //Output:- Hello World
finalString = finalString.stringByAppendingFormat("%@", " Of People")
print(finalString) //Output:- Hello World Of People

Answer 13

You could use SwiftString (https://github.com/amayne/SwiftString) to do this.

"".join(["string1", "string2", "string3"]) // "string1string2string"
" ".join(["hello", "world"]) // "hello world"

DISCLAIMER: I wrote this extension

Answer 14

Swift 4.2

You can also use an extension:

extension Array where Element == String? {
    func compactConcate(separator: String) -> String {
        return self.compactMap { $0 }.filter { !$0.isEmpty }.joined(separator: separator)
    }
}

Use:

label.text = [m.firstName, m.lastName].compactConcate(separator: " ")

Result:

"The Man"
"The"
"Man"

Answer 15

I just switched from Objective-C to Swift (4), and I find that I often use:

let allWords = String(format:"%@ %@ %@",message.body!, message.subject!, message.senderName!)

Answer 16

In Swift 5 apple has introduces Raw Strings using # symbols.

Example:

print(#"My name is "XXX" and I'm "28"."#)
let name = "XXX"
print(#"My name is \#(name)."#)

symbol # is necessary after \. A regular \(name) will be interpreted as characters in the string.