Iterating Over Elements

Now that you know how to create and modify arrays, let's explore how to process each element one by one. The for-in loop makes this incredibly straightforward.

When you use a for-in loop with an array, Swift automatically gives you each element in order:

let fruits = ["Apple", "Banana", "Cherry"]

for fruit in fruits {
    print(fruit)
}
// Apple
// Banana
// Cherry

The variable fruit takes on each value from the array during each iteration. You can name this variable anything that makes sense for your data.

This pattern is perfect for performing operations on every element, like calculating a total:

let prices = [9.99, 14.50, 3.25]
var total = 0.0

for price in prices {
    total += price
}

print(total)  // 27.74

You can also use the loop to build new arrays based on existing ones:

let numbers = [1, 2, 3, 4]
var doubled = [Int]()

for number in numbers {
    doubled.append(number * 2)
}

print(doubled)  // [2, 4, 6, 8]

Iterating over arrays is one of the most common operations in programming, so mastering this pattern will serve you well.