Copy All Elements of One Array to Another in Swift

In this article, we will learn how to write a swift program to copy all the elements of one array to another array. Swift doesn't provide a direct method to copy the elements of one array to another but we can do this using the following methods ?

• Using map(_:) method

• Using = operator

• Using append(contentsOf:) method

Method 1: Using map(_:) method

The map(_:) method is used to return an array that contains the result of mapping the given closure over the specified sequence's elements.

Syntax

func map<T>(_mclosure:(Self.Element) throws - >T)rethrows [T]

Here, mclouser is a mapping closure, it accepts the elements of the specified sequence and return a transformed value of the same or different type.

Algorithm

Step 1 ? Create an array with values.

Step 2 ? Create another array of same type but empty.

Step 3 ? Copy the elements of array1 into array 2 using map(_:) function.

Array2 = Array1.map { $0 }

Step 4 ? Print the output.

Example

Following Swift program to copy all the elements of one array to another array.

import Foundation
import Glibc
let Array1 = [11, 22, 33, 44, 55]
var Array2 = [Int]()

// Copying the element of array1 into array2

// Using map
Array2 = Array1.map { $0 }
print("Original array: ", Array1)
print("New array: ", Array2)

Output

Original array: [11, 22, 33, 44, 55]
New array: [11, 22, 33, 44, 55]

Here in the above code, we have two arrays named Array1 with values and Array2 without values. Now to copy the elements of Array1 into Array2 we pass a closure that is {$0} in the map(_:) function which copies all the elements of Array1 starting from index 0 to the last index into the Array2.

Method 2: Using = operator

To copy the elements of one array to another we can also use the assignment operator. This operator assigns the values of the right-hand side operand to left and side operand.

Syntax

Array2 = Array1

Here, both Array1 and Array2 are of same type and the assignment operator assign the elements of Array1 to Array2.

Algorithm

Step 1 ? Create an array with values.

Step 2 ? Create another array of the same type but empty.

Step 3 ? Copy the elements of array1 into array 2 using the assignment operator.

Darray = Sarray

Step 4 ? Print the output.

Example

Following the Swift program to copy all the elements of one array to another array

import Foundation
import Glibc
let Sarray = [10, 20, 30, 40, 50]

// Create an empty array with the same type as Sarray
var Darray = [Int]()

// Copy all the elements of Sarray to Darray
Darray = Sarray
print("Array 1:", Sarray)
print("Array 2:", Darray)

Output

Array 1: [10, 20, 30, 40, 50]
Array 2: [10, 20, 30, 40, 50]

Here in the above code, we have two arrays named Array1 with values and Array2 without values. Now to copy the elements of Array1 into Array2 we use the assignment operator. This operator assigns all the elements of Array1 into Array2.

Method 3: Using append(contentsOf:) Method

To copy the elements of one array to another we can also use append(contentsOf:) method. This method adds the elements of the given array or sequence to the end of the new array.

Syntax

func append<S>(contentsOf nElement: S) where Element == s.Element, S.Sequence

Here, nElement is the sequence whose elements are going to append into the specified array.

Algorithm

Step 1 ? Create an array with values.

Step 2 ? Create another array of the same type but empty.

Step 3 ? Copy the elements of array1 into array 2 using append(contentsOf:) method.

Array2.append(contentsOf: Array1)

Step 4 ? Print the output.

Example

Following Swift program to copy all the elements of one array to another array

import Foundation
import Glibc
let Array1 = ["Ox", "Cow", "Bee", "Cat", "Dog"]

// Create an empty array with the same type as array1
var Array2 = [String]()

// Copy all the elements of array1 to array2

// Using append(:) method
Array2.append(contentsOf: Array1)
print("Original array:", Array1)
print("New array:", Array2) 

Output

Original array: ["Ox", "Cow", "Bee", "Cat", "Dog"]
New array: ["Ox", "Cow", "Bee", "Cat", "Dog"]

Here in the above code, we have two arrays named Array1 with values and Array2 without values. To copy the elements of Array1 into Array2 we use append(contentsOf:) method. In this method, we pass Array1 as the value of the contentsOf parameter. Now, this method append all the elements of Array1 into Array2.

Conclusion

So this is how we can copy all the elements of one array to another array using map(_:) method, = operator, and append(contentsOf:) method. Because Swift does not provide a library function to copy the elements of the array just like Java. Java has an in-built library function named arraycopy() to copy the array elements.