Arrays

An array stores multiple values of the same type in an ordered list.

Creating Arrays

var fruits = ["Apple", "Banana", "Cherry"]
var emptyArray: [String] = []
var anotherEmptyArray = [String]() // Alternative way to create an empty array
var repeatedArray = Array(repeating: 0, count: 5) // [0, 0, 0, 0, 0]

Accessing and Modifying

Arrays are 0-indexed.

print(fruits[0]) // "Apple"

fruits.append("Date")
fruits += ["Elderberry"]
fruits[1] = "Blueberry" // Changing an element

Common Operations

Operation	Description
.count	The total number of elements.
.isEmpty	Checks if the array has no elements.
.first	Returns the first element.
.last	Returns the last element.
.contains(_:)	Checks if a specific value exists.
.append(_:)	Adds a new element to the end.
.insert(_:at:)	Adds a new element at a specific index.
.remove(at:)	Removes the element at a specific index.
.removeAll()	Empties the entire array.
.reversed()	Returns the elements in reverse order.

if !fruits.isEmpty {
    print("We have \(fruits.count) fruits.")
}

Sorting Arrays

It is important to understand the difference between modifying an array in place and creating a new sorted copy.

• sort(): Sorts the original array directly. The array must be a variable (var).
• sorted(): Leaves the original array unchanged and returns a completely new array containing the sorted elements.

Iterating over Arrays

for fruit in fruits {
    print("I like \(fruit)")
}

If you need to work with both the item and its exact position, the enumerated() method is the best approach. It pairs each element with its index, making it highly effective for numbered lists.

for (index, value) in fruits.enumerated() {
    print("Item \(index + 1): \(value)")
}

To loop through just the index numbers without accessing the underlying elements directly, use the indices property.

for index in fruits.indices {
    print("Index position: \(index)")
}

NOTE

Arrays declared with let are immutable; you cannot add, remove, or change their elements.