Array Methods

Part of the Fundamentals section of Coddy's Swift journey — lesson 65 of 86.

Beyond adding and removing elements, Swift arrays come with several helpful methods that make working with collections easier.

The isEmpty property checks whether an array has any elements:

var tasks = [String]()
print(tasks.isEmpty)  // true

tasks.append("Buy groceries")
print(tasks.isEmpty)  // false

To remove all elements at once, use removeAll():

var numbers = [1, 2, 3, 4, 5]
numbers.removeAll()
print(numbers)  // []

The reversed() method returns the elements in reverse order:

let letters = ["A", "B", "C"]
print(Array(letters.reversed()))  // ["C", "B", "A"]

For sorting, use sorted() to get a new sorted array, or sort() to sort the array in place:

let scores = [85, 42, 97, 63]
print(scores.sorted())  // [42, 63, 85, 97]

var prices = [9.99, 2.50, 5.75]
prices.sort()
print(prices)  // [2.5, 5.75, 9.99]

Notice that sorted() returns a new array while leaving the original unchanged, whereas sort() modifies the original array directly.

Challenge

Easy

Write a function processScores that takes scores and returns a formatted string with information about the scores.

The function should analyze the array and build a result string with three pieces of information.

Logic:

Check if the array is empty using isEmpty
If empty, return "No scores"
Otherwise, get the sorted scores (ascending order) and the reversed scores
Return a string combining both results

Parameters:

scores ([Int]): An array of integer scores

Returns: A string in the format: "Sorted: [sorted_array], Reversed: [reversed_array]" or "No scores" if the array is empty (String)

Example: If scores is [85, 42, 97, 63], the function should return:

"Sorted: [42, 63, 85, 97], Reversed: [63, 97, 42, 85]"

Note: The reversed array should be the reverse of the original array, not the sorted one.

Cheat sheet

Swift arrays provide several useful methods for working with collections:

The isEmpty property checks if an array contains any elements:

var tasks = [String]()
print(tasks.isEmpty)  // true

tasks.append("Buy groceries")
print(tasks.isEmpty)  // false

Use removeAll() to remove all elements from an array:

var numbers = [1, 2, 3, 4, 5]
numbers.removeAll()
print(numbers)  // []

The reversed() method returns elements in reverse order:

let letters = ["A", "B", "C"]
print(Array(letters.reversed()))  // ["C", "B", "A"]

For sorting, use sorted() to create a new sorted array, or sort() to sort in place:

let scores = [85, 42, 97, 63]
print(scores.sorted())  // [42, 63, 85, 97]

var prices = [9.99, 2.50, 5.75]
prices.sort()
print(prices)  // [2.5, 5.75, 9.99]

sorted() returns a new array without modifying the original, while sort() modifies the array directly.

Try it yourself

func processScores(scores: [Int]) -> String {
    // Write code here
}

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Fundamentals

1Introduction

The Language Hello World!Comments

4Operators Part 1

Arithmetic Operators Modulo Operator Compound Assignment Recap - Simple Math Comparison Operators

7Basic IO

Print Function String Interpolation ReadLine Input Type Conversion Recap - Till 120 Recap - True or False

10Functions

Declare A Function Parameters And Arguments Return Values Argument Labels Recap - Sigma Function Recap - Validation Function Default Values

13Iterating Over Sequences

Iterating Over Elements The Enumerated Method Iterating Over Strings P1 Iterating Over Strings P2

16Final Challenges

Flat Asterisk Pyramid Pattern Finder What To Buy

2Variables

Let vs Var Type Annotations Numbers String Boolean Naming Conventions Recap - Initialize Variables

5Operators Part 2

Logical Operators Part 1 Logical Operators Part 2 Recap - Simple Logic Logical Operators Part 3 Ternary Operator

8Bill Split Calculator

Welcome Message Getting Input

Calculating Tip And Total

Splitting The Bill

Formatted Output

11FizzBuzz with a Twist

Game Overview The FizzBuzz Function

Looping The Numbers

Adding The Twist

14Arrays Advanced

Array Slicing Part 1 Array Slicing Part 2 Sequence Operators The Contains Method