Add an element to an array in Swift

Question

Suppose I have an array, for example:

var myArray = ["Steve", "Bill", "Linus", "Bret"]

And later I want to push/append an element to the end of said array, to get:

["Steve", "Bill", "Linus", "Bret", "Tim"]

What method should I use?

And what about the case where I want to add an element to the front of the array? Is there a constant time unshift?

Solution 1

As of Swift 3 / 4 / 5, this is done as follows.

To add a new element to the end of an Array.

anArray.append("This String")

To append a different Array to the end of your Array.

anArray += ["Moar", "Strings"]
anArray.append(contentsOf: ["Moar", "Strings"])

To insert a new element into your Array.

anArray.insert("This String", at: 0)

To insert the contents of a different Array into your Array.

anArray.insert(contentsOf: ["Moar", "Strings"], at: 0)

More information can be found in the "Collection Types" chapter of "The Swift Programming Language", starting on page 110.

Solution 2

You can also pass in a variable and/or object if you wanted to.

var str1:String = "John"
var str2:String = "Bob"

var myArray = ["Steve", "Bill", "Linus", "Bret"]

//add to the end of the array with append
myArray.append(str1)
myArray.append(str2)

To add them to the front:

//use 'insert' instead of append
myArray.insert(str1, atIndex:0)
myArray.insert(str2, atIndex:0)

//Swift 3
myArray.insert(str1, at: 0)
myArray.insert(str2, at: 0)

As others have already stated, you can no longer use '+=' as of xCode 6.1

Solution 3

To add to the end, use the += operator:

myArray += ["Craig"]
myArray += ["Jony", "Eddy"]

That operator is generally equivalent to the append(contentsOf:) method. (And in really old Swift versions, could append single elements, not just other collections of the same element type.)

There's also insert(_:at:) for inserting at any index.

If, say, you'd like a convenience function for inserting at the beginning, you could add it to the Array class with an extension.

Solution 4

Use += and + operators :

extension Array {

}

func += <V> (inout left: [V], right: V) {
    left.append(right)
}

func + <V>(left: Array<V>, right: V) -> Array<V>
{
    var map = Array<V>()
    for (v) in left {
        map.append(v)
    }

    map.append(right)

    return map
}

then use :

var list = [AnyObject]()
list += "hello" 
list += ["hello", "world!"]
var list2 = list + "anything"

Solution 5

In Swift 4.1 and Xcode 9.4.1

We can add objects to Array basically in Two ways

let stringOne = "One"
let strigTwo = "Two"
let stringThree = "Three"
var array:[String] = []//If your array is string type

Type 1)

//To append elements at the end
array.append(stringOne)
array.append(stringThree)

Type 2)

//To add elements at specific index
array.insert(strigTwo, at: 1)

If you want to add two arrays

var array1 = [1,2,3,4,5]
let array2 = [6,7,8,9]

let array3 = array1+array2
print(array3)
array1.append(contentsOf: array2)
print(array1)

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