How to Access Elements of Swift Array using Index?

Swift – Access Elements of Array using Index

To access elements of a Swift Array using Index, use the index as subscript on the array variable.

The syntax to access element of an array at specific index is

var element = arrayName[index]

where

• arrayName is the array from which we would like to access the element, and
• index is the integer which represents the position of element in the array.

The index starts at 0, and increments in steps of 1 until the length of the array. Which means the first element of a nonempty array is always at index zero

A negative index or an index equal to or greater than array length triggers a runtime error.

Examples

In the following program, we will create an array with file elements and get the elements at index 1 and 3 respectively.

main.swift

var fruits: [String] = ["apple", "banana", "cherry", "mango", "guava"]

//element at index = 1
let element_1 = fruits[1]
print("Element at index=1 is \(element_1)")

//element at index = 3
let element_3 = fruits[3]
print("Element at index=3 is \(element_3)")

Output

Negative Index

If we try to access an array with negative number as index, we get runtime error, as shown in the following program.

main.swift

var fruits: [String] = ["apple", "banana", "cherry", "mango", "guava"]

//element at index = -2
let element_1 = fruits[-2]
print("Element at index=-2 is \(element_1)")

Output

Index >= Array Length

If we try to access an array with an index greater than the array length, we get runtime error, as shown in the following program.

main.swift

var fruits: [String] = ["apple", "banana", "cherry", "mango", "guava"]

//element at index = 8
let element_1 = fruits[8]
print("Element at index=8 is \(element_1)")

Output

Conclusion

In this Swift Tutorial, we learned how to access elements of an array using index.